Lubricating oil compositions for electric vehicle powertrains

ABSTRACT

This disclosure relates to a lubricating oil for an electric vehicle powertrain and powertrain components. The lubricating oil has a composition including a lubricating base oil as a major component, an additive package, as a minor component, and an effective amount of one or more conductivity agents, as a minor component. The lubricating oil has an electrical conductivity from about 10 pS/m to about 20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, with a ratio of electrical conductivity-to-dielectric constant from about 5 to about 10,000. This disclosure also relates to methods for producing a lubricating oil for an electric vehicle powertrain and powertrain components.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 62/405,283 filed Oct. 7, 2016, which is herein incorporated byreference in its entirety. This application is also related to fourcopending U.S. applications, filed on even date herewith, amd identifiedby the following Attorney Docket numbers and titles: 2016EM272-US2entitled “Method for Controlling Electrical Conductivity of LubricatingOils in Electric Vehicle Powertrains”; 2016EM273-US2 entitled “Methodfor Preventing or Minimizing Electrostatic Discharge and DielectricBreakdown in Electric Vehicle Powertrains”; 2017EM320 entitled “LowConductivity Lubricating Oils For Electric And Hybrid Vehicles”; and2017EM319 entitled “High Conductivity Lubricating Oils For Electric AndHybrid Vehicles”. Each of these co-pending US applications is herebyincorporated by reference herein in its entirety.

FIELD

This disclosure provides lubricating oils for an electric vehiclepowertrain and powertrain components. This disclosure also providesmethods for producing a lubricating oil for an electric vehiclepowertrain and powertrain components.

BACKGROUND

A major challenge in electric vehicle powertrain lubricant formulatingis controlling lubricant electrical conductivity over the lifetime ofthe lubricant. In particular, the challenge to electric vehiclepowertrain lubricant compositions is achieving oxidation stability,deposit control, corrosion inhibition, and lubricant compatability withelectric vehicle powertrain components and materials over a broadtemperature range.

For example, copper is present in the electric systems of electricvehicle powertrains and requires protection at high temperatures.Planetary gear sets, typically fabricated from ferrous alloys andsteels, are used in electric vehicle powertrains and also require goodprotection. Suitable lubricant compositions, however, may usesulfur-containing performance additives in achieving good gearprotection, but on balance, may limit sulfur concentrations in order toachieve good copper protection.

Additionally, in electric vehicle powertrains, lubricant electricalconductivity needs to be at the right level and maintained over theservice lifetime of the lubricating fluid. If lubricant electricalconductivity is too low, then arcing (e.g., electrostatic buildup anddischarge) among the electrified system components can occur. Iflubricant electrical conductivity is too high, then the electric vehiclepowertrains will adversely leak charge.

Also, oil-derived lubricating properties must be maintained despiteexposure to high surface temperatures of electric powertrain components.However, this lube stability must be balanced with other lubricantproperties such as low viscosity and achieving good gear protection.

Despite advances in lubricant oil technology in electric vehicles, thereexists a need for an electric vehicle powertrain lubricant compositionhaving desired lubricant electrical conductivity over the lifetime ofthe lubricant. In particular, there is a need for electric vehiclepowertrain lubricant composition having oxidation stability, depositcontrol, corrosion inhibition, and lubricant compatability with electricvehicle powertrain components and materials over a broad temperaturerange.

SUMMARY

This disclosure relates in part to a lubricating oil for an electricvehicle powertrain. The lubricating oil has a composition comprising alubricating base oil as a major component; one or more lubricating oiladditives, as a minor component; and an effective amount of one or moreconductivity agents, as a minor component. The lubricating oil has anelectrical conductivity from about 10 pS/m to about 20,000 pS/m, adielectric constant of about 1.6 to about 3.6, with a ratio ofelectrical conductivity-to-dielectric constant from about 5 to about10,000.

This disclosure also relates in part to a lubricating oil for anelectric vehicle powertrain. The lubricating oil has a compositioncomprising a lubricating base oil as a major component, and one or morelubricating oil additives, as a minor component, and an effective amountof one or more conductivity agents, as a minor component. Thelubricating oil has an electrical conductivity from about 10 pS/m toabout 20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, witha ratio of electrical conductivity-to-dielectric constant from about 5to about 10,000, a kinematic viscosity from about 2 cSt to about 20 cStat 100° C., a total acid number (TAN) less than about 3, less than about200 ppm active sulfur, and a viscosity index (VI) greater than about 50.

This disclosure also relates in part to a lubricating oil for anelectric vehicle powertrain. The lubricating oil has a compositioncomprising at least about 70 weight percent of a lubricating base oil,from about 0.01 to about 30 weight percent of an additive package,wherein comprises one or more of from about 0.01 to about 5 weightpercent of an antioxidant, from about 0.01 to about 10 weight percent ofa detergent, from about 0.01 to about 20 weight percent of a dispersant,from about 0.01 to about 5 weight percent of an antiwear agent, fromabout 0.01 to about 5 weight percent of a corrosion inhibitor, fromabout 0 to about 20 weight percent of a viscosity modifier, from about0.01 to about 5 weight percent of a metal passivator, and from about0.01 to about 30 weight percent of a conductivity agent. Each weightpercent is based on the total weight of the lubricating oil. Thelubricating oil has an electrical conductivity from about 10 pS/m toabout 20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, witha ratio of electrical conductivity-to-dielectric constant from about 5to about 10,000, a kinematic viscosity from about 2 cSt to about 20 cStat 100° C., a total acid number (TAN) less than about 3, less than about200 ppm active sulfur, and a viscosity index (VI) greater than about 50.

This disclosure further relates in part to a method for producing alubricating oil for an electric vehicle powertrain. The method comprisesproviding a lubricating base oil as a major component; one or morelubricating oil additives, as a minor component; and an effective amountof one or more conductivity agents, as a minor component and blendingthe at least one lubricating oil basestock, the one or more lubricatingoil additives, and the one or more conductivity agents to produce thelubricating oil. The lubricating oil has an electrical conductivity fromabout 10 pS/m to about 20,000 pS/m, a dielectric constant of about 1.6to about 3.6, with a ratio of electrical conductivity-to-dielectricconstant from about 5 to about 10,000.

This disclosure also further relates in part to a method for producing alubricating oil for an electric vehicle powertrain. The method comprisesproviding a lubricating base oil as a major component; one or morelubricating oil additives, as a minor component; and an effective amountof one or more conductivity agents, as a minor component and blendingthe at least one lubricating oil basestock, the one or more lubricatingoil additives, and the one or more conductivity agents to produce thelubricating oil. The lubricating oil has an electrical conductivity fromabout 10 pS/m to about 20,000 pS/m, a dielectric constant of about 1.6to about 3.6, with a ratio of electrical conductivity-to-dielectricconstant from about 5 to about 10,000, a kinematic viscosity from about2 cSt to about 20 cSt at 100° C., a total acid number (TAN) less thanabout 3, less than about 200 ppm active sulfur, and a viscosity index(VI) greater than about 50.

This disclosure still also further relates in part to a method forproducing a lubricating oil for an electric vehicle powertrain. Themethod comprises providing at least one lubricating oil basestock,providing one or more lubricating oil additives, providing one or moreconductivity agents, and blending the at least one lubricating oilbasestock, the one or more lubricating oil additives, and the one ormore conductivity agents in amounts sufficient to produce thelubricating oil. The lubricating oil has a composition comprising atleast about 70 weight percent of a lubricating base oil, from about 0.01to about 5 weight percent of an antioxidant, from about 0.01 to about 10weight percent of a detergent, from about 0.01 to about 20 weightpercent of a dispersant, from about 0.01 to about 5 weight percent of anantiwear agent, from about 0.01 to about 5 weight percent of a corrosioninhibitor, from about 0 to about 20 weight percent of a viscositymodifier, from about 0.01 to about 5 weight percent of a metalpassivator, and from about 0.01 to about 30 weight percent of aconductivity agent. Each weight percent is based on the total weight ofthe lubricating oil. The lubricating oil has an electrical conductivityfrom about 10 pS/m to about 20,000 pS/m, a dielectric constant of about1.6 to about 3.6, with a ratio of electrical conductivity-to-dielectricconstant from about 5 to about 10,000, a kinematic viscosity from about2 cSt to about 20 cSt at 100° C., a total acid number (TAN) less thanabout 3, less than about 200 ppm active sulfur, and a viscosity index(VI) greater than about 50.

It has been surprisingly found that, in accordance with this disclosure,improvement in lubricant electrical conductivity control is obtained inan electric vehicle powertrain lubricated with a lubricating oil, byincluding one or more lubricating oil additives in the lubricating oil(e.g., antioxidant, detergent, dispersant, antiwear agent, corrosioninhibitor, viscosity modifier, and metal passivator). The addition ofthe one or more lubricating oil additives affords greater improvementsin oxidation stability, deposit control, corrosion inhibition, andlubricant compatability with electric vehicle powertrain components andmaterials over a broad temperature range.

Further it has been surprisingly found that, in accordance with thisdisclosure, improvement in lubricant electrical conductivity control isobtained, and at least one of oxidation stability, deposit control,corrosion inhibition, and lubricant compatability with electric vehiclepowertrain components and materials over a broad temperature range, ismaintained or improved as compared to lubricant electrical conductivitycontrol, oxidation stability, deposit control, corrosion inhibition, andlubricant compatability with electric vehicle powertrain components andmaterials over a broad temperature range, achieved using a lubricatingoil containing a minor component other than the one or more lubricatingoil additives. The addition of the one or more lubricating oil additivesaffords greater improvements in lubricant electrical conductivitycontrol, while maintaining or improving at least one of oxidationstability, deposit control, corrosion inhibition, and lubricantcompatability with electric vehicle powertrain components and materialsover a broad temperature range.

This disclosure relates to lubricating oils that include, for example,oils of lubricating viscosity, working fluids, and oil-based coolants.This disclosure also relates to the lubrication of electric vehiclesthat comprise electric vehicle powertrains that include, for example,electric vehicle powertrain systems, electromechanical systems,drivetrain systems, kinetic energy recovery systems, or combinationsthereof. In this disclosure, electric vehicles include, for example,all-electric and fully electric vehicles, and hybrid or hybrid electricvehicles, which may have any of a variety of parallel or seriesconfigurations, alone or in combination.

Other objects and advantages of the present disclosure will becomeapparent from the detailed description that follows.

DETAILED DESCRIPTION

All numerical values within the detailed description and the claimsherein are modified by “about” or “approximately” the indicated value,and take into account experimental error and variations that would beexpected by a person having ordinary skill in the art.

It has now been found that improved lubricant electrical conductivitycontrol can be attained in an electric vehicle powertrain lubricatedwith a lubricating oil that has one or more lubricating oil additives(for example, antioxidant, detergent, dispersant, antiwear additive,corrosion inhibitor, viscosity modifier, metal passivator, pour pointdepressant, seal compatibility agent, antifoam agent, extreme pressureagent, friction modifier, and mixtures thereof), and one or moreconductivity agents in the lubricating oil. Conductivity agents increasethe conductivity of a lubricating or working fluid by a tangiblequantity, for example, an increment of +100 pS/m or more, when added tosuch fluid in an effective amount. The lubricating oil has a compositioncomprising a lubricating base oil as a major component, the one or morelubricating oil additives, as a minor component, and the one or moreconductivity agents, as a minor component. The lubricating oils of thisdisclosure are particularly advantageous as passenger electric vehiclepowertrain oil products. The lubricating oils that contain one or morelubricating oil additives are particularly useful in controllingelectrical conductivity in low viscosity electric vehicle powertrainoils. In one aspect, the lubricating oils of this disclosure thatcontain one or more lubricating oil additives are particularly useful incontrolling lubricant electrical conductivity to improve bearing-relatedelectric discharge performance, where the ratio ofconductivity-to-dielectric constant is equal to or greater than about1,000 and may particularly range from about 1,000 to about 10,000. Inanother aspect, the lubricating oils of this disclosure that contain oneor more lubricating oil additives are particularly useful in controllinglubricant electrical conductivity to minimize battery drainage andimprove battery lifetime, where the ratio of conductivity-to-dielectricconstant is less than about 1,000.

In an embodiment, lubricant electrical conductivity control in electricvehicle powertrains is improved and at least one of oxidation stability,deposit control, corrosion inhibition, and lubricant compatability withelectric vehicle powertrain components and materials over a broadtemperature range, are maintained or improved as compared to lubricantelectrical conductivity control, oxidation stability, deposit control,corrosion inhibition, and lubricant compatability with electric vehiclepowertrain components and materials over a broad temperature range,achieved using a lubricating oil containing a minor component other thanthe one or more lubricating oil additives.

The lubricant compositions of this disclosure provide advantagedlubricant electrical conductivity control, including advantagedoxidation stability, deposit control and corrosion inhibition,performance in the lubrication of electric vehicle powertrains. Electricvehicle powertrains comprise, for example, one or more of drivelines,transmissions, differentials, gears, gear trains, gear sets, gear boxes,bearings, bushings, axles [front axle(s) and/or rear axle(s)], turbines,compressors, pumps, hydraulic systems, batteries, capacitors, electricmotors, drive motors, generators, AC/DC converters, alternators,transformers, kinetic energy converters, kinetic energy recoverysystems, and the like. In an embodiment, a single lubricant compositionis used in the electric vehicle powertrain. In another embodiment, morethan one lubricant composition is used in the electric vehiclepowertrain, for example, one lubricant composition for the transmissionand another lubricant composition for another component of thepowertrain. An electric vehicle powertrain system includes thecombination of an electric vehicle powertrain (and powertraincomponents) and a lubricating oil or working fluid that are used in suchservice.

Yet further, the lubricant compositions of this disclosure provideadvantaged lubricant electrical conductivity control, includingadvantaged oxidation stability, deposit control and corrosioninhibition, performance under diverse lubrication regimes of electricvehicle powertrains, that include, for example, hydrodynamic,elastohydrodynamic, boundary, mixed lubrication, extreme pressureregimes, and the like.

The lubricant compositions of this disclosure provide advantagedlubricant electrical conductivity control, including advantagedoxidation stability, deposit control and corrosion inhibition,performance in electric vehicle powertrains under a range of lubricationcontact pressures, from 1 MPas to greater than 10 GPas, preferablygreater than 10 MPas, more preferably greater than 100 MPas, even morepreferably greater than 300 MPas. Under certain circumstances, thelubricant compositions of this disclosure provide advantaged lubricantelectrical conductivity control, including advantaged oxidationstability, deposit control and corrosion inhibition, performance inelectric vehicle powertrains at greater than 0.5 GPas, often at greaterthan 1 GPas, sometimes greater than 2 GPas, under selected circumstancesgreater than 5 GPas.

Further, the lubricant compositions of this disclosure provideadvantaged lubricant electrical conductivity control, includingadvantaged oxidation stability, deposit control and corrosioninhibition, performance on lubricated surfaces of electric vehiclepowertrains, that include, for example, the following: metals, metalalloys, non-metals, non-metal alloys, mixed carbon-metal composites andalloys, mixed carbon-nonmetal composites and alloys, ferrous metals,ferrous composites and alloys, non-ferrous metals, non-ferrouscomposites and alloys, titanium, titanium composites and alloys,aluminum, aluminum composites and alloys, magnesium, magnesiumcomposites and alloys, ion-implanted metals and alloys, plasma modifiedsurfaces; surface modified materials; coatings; mono-layer, multi-layer,and gradient layered coatings; honed surfaces; polished surfaces; etchedsurfaces; textured surfaces; micro and nano structures on texturedsurfaces; super-finished surfaces; diamond-like carbon (DLC), DLC withhigh-hydrogen content, DLC with moderate hydrogen content, DLC withlow-hydrogen content, DLC with near-zero hydrogen content, DLCcomposites, DLC-metal compositions and composites, DLC-nonmetalcompositions and composites; ceramics, ceramic oxides, ceramic nitrides,FeN, CrN, ceramic carbides, mixed ceramic compositions, cermets, and thelike; polymers, thermoplastic polymers, engineered polymers, polymerblends, polymer alloys, polymer composites; materials compositions andcomposites containing dry lubricants, that include, for example,graphite, carbon, molybdenum, molybdenum disulfide,polytetrafluoroethylene, polyperfluoropropylene,polyperfluoroalkylethers, and the like; super hydrophobic surfaces;super hydrophilic surfaces; self-healing surfaces; surfaces derived from3-D printing or additive manufacturing techniques, which may beadditionally used as-manufactured, or used with post-printing surfacefinishing, or used with post-printing surface coating.

Still further, the lubricant compositions of this disclosure provideadvantaged lubricant electrical conductivity control, includingadvantaged oxidation stability, deposit control and corrosioninhibition, performance in electric vehicle powertrains with the one ormore lubricating oil additives at effective concentration ranges and ateffective ratios in accordance with this disclosure.

As used herein, electrical conductivity is determined in accordance withASTM D2624 (modified), using Model 1153 Digital Conductivity Meter.Dielectric constant measurements were performed using ASTM D924 and TECFPP8 800. Kinematic viscosity is determined by ASTM D445, total acidnumber (TAN) is determined by ASTM D974, metals content is determined byASTM D6376, active sulfur content is determined by ASTM D129, viscosityindex (VI) is determined by ASTM D2270, density is determined by ASTMD4052, and specific heat capacity is determined by ASTM D1269.

In an embodiment, the lubricating oils of this disclosure have anelectrical conductivity of greater than about 10 pS/m, or greater thanabout 50 pS/m, or greater than about 100 pS/m, or greater than about 300pS/m, or greater than about 600 pS/m, or greater than about 1,000 pS/m,or greater than about 2,000 pS/m, or greater than about 3,000 pS/m, orgreater than about 4,000 pS/m, or greater than about 5,000 pS/m, orgreater than about 6,000 pS/m, or greater than about 8,000 pS/m, orgreater than about 10,000 pS/m, or greater than about 15,000 pS/m, orgreater than about 20,000 pS/m. In another embodiment, the lubricatingoils of this disclosure have an electrical conductivity of from about 10pS/m to about 20,000 pS/m, or from about 50 pS/m to about 19,000 pS/m,or from about 100 pS/m to about 18,000 pS/m, or from about 1,000 pS/m toabout 18,000 pS/m, or from about 200 pS/m to about 17,000 pS/m, or fromabout 200 pS/m to about 16,000 pS/m, or from about 400 pS/m to about16,000 pS/m, or from about 1,000 pS/m to about 16,000 pS/m, or fromabout 500 pS/m to about 15,000 pS/m, or from about 600 pS/m to about14,000 pS/m, or from about 1,000 pS/m to about 14,000 pS/m, or fromabout 700 pS/m to about 13,000 pS/m, or from about 800 pS/m to about12,000 pS/m, or from about 1,000 pS/m to about 12,000 pS/m, or fromabout 900 pS/m to about 11,000 pS/m, or from about 1,000 pS/m to about10,000 pS/m, or from about 1,000 pS/m to about 8,000 pS/m, or from about1,000 pS/m to about 6,000 pS/m.

In an embodiment, the lubricating oils of this disclosure have adielectric constant from about 1.6 to about 3.6, or from about 1.8 toabout 3.5, or from about 2 to about 3.4, or from about 2.1 to about 3.2,or from about 2.2 to about 3, or from about 2.2 to about 2.8, or fromabout 2.2 to about 2.7, or from about 2.2 to 2.6, or about 2.2 to 2.5.

In an embodiment, the lubricating oils of this disclosure have a ratioof conductivity-to-dielectric constant equal to or greater than about1,000, or greater than about 1,200, or greater than about 1,400, orgreater than about 1,600, or greater than about 1,800, or greater thanabout 2,000, or greater than about 2,500, or greater than about 3,000,or greater than about 4,000, or greater than about 5,000, or greaterthan about 6,000, or greater than about 7,000, or greater than about8,000, or greater than about 10,000. In another embodiment, thelubricating oils of this disclosure have a ratio ofconductivity-to-dielectric constant from about 1,000 to about 10,000, orabout 1,200 to about 9,000, or about 1,400 to about 8,000, or about1,600 to about 7,000, or about 1,800 to about 6,000, or about 1,800 toabout 5,000, or about 1,800 to about 4,000.

In an embodiment, the lubricating oils of this disclosure have a ratioof conductivity-to-dielectric constant less than about 1,000, or lessthan about 900, or less than about 800, or less than about 700, or lessthan about 600, or less than about 500, or less than about 400, or lessthan about 300, or less than about 200, or less than about 100, or lessthan about 50, or less than about 20, or less than about 10. In anotherembodiment, the lubricating oils of this disclosure have a ratio ofconductivity-to-dielectric constant from less than about 1,000 to about5, or about 900 to about 5, or about 800 to about 10, or about 700 toabout 10, or about 600 to about 10, or about 600 to about 20, or about600 to about 40, or about 600 to about 60.

In an embodiment, the lubricating oils of this disclosure have akinematic viscosity at 100° C. from about 2 cSt to about 20 cSt, or fromabout 3 cSt to about 18 cSt, or from about 3 cSt to about 14 cSt, orfrom about 3 cSt to about 10 cSt, or from about 4 cSt to about 16 cSt,or from about 5 cSt to about 14 cSt, or from about 6 cSt to about 12cSt, or from about 8 cSt to about 12 cSt.

In an embodiment, the lubricating oils of this disclosure have a totalacid number (TAN) less than about 3, or less than about 2.8, or lessthan about 2.6, or less than about 2.4, or less than about 2.2, or lessthan about 2, or less than about 1.8, or less than about 1.6, or lessthan about 1.4, or less than about 1.2, or less than about 1, or lessthan about 0.8, or less than about 0.6, or less than about 0.4, or lessthan about 0.2.

In an embodiment, the lubricating oils of this disclosure have less thanabout 200 ppm active sulfur, or less than about 100 ppm active sulfur,or less than about 75 ppm active sulfur, or less than about 50 ppmactive sulfur, or less than about 25 ppm active sulfur, or less thanabout 10 ppm active sulfur, or no sulfur.

As used herein, active sulfur is the type of sulfur that reacts withsurfaces at low temperatures and is corrosive to such surfaces,especially yellow metals (e.g., brass, bronze, copper, and the like).Active sulfur is chemically aggressive, and with yellow metals beingsofter than steel, they can begin to pit and form spalls due to thischemical attack. Active sulfur, when in contact with copper along withthe presence of heat, forms copper sulfide. This simple chemicalreaction can have devastating repercussions on the reliability ofelectric vehicle powertrains. In extreme pressure situations, copperdisulfide can be formed. Both of these crystalline forms of copper arevery hard and can cause abrasive damage to powertrain surfaces. Incontrast, inactive sulfur only reacts with surfaces at hightemperatures.

In an embodiment, the lubricating oils of this disclosure have aviscosity index (VI) greater than about 50, or greater than about 60, orgreater than about 70, or greater than about 80, or greater than about90, or greater than about 100, or greater than about 110, or greaterthan about 120.

In an embodiment, the lubricating oils of this disclosure have afinished lubricant density of greater than about 0.8 g/mL, or greaterthan about 0.82 g/mL, or greater than about 0.84 g/mL, or greater thanabout 0.86 g/mL, or greater than about 0.88 g/mL, or greater than about0.9 g/mL, or greater than about 0.92 g/mL, or greater than about 0.94g/mL, or greater than about 0.96 g/mL, or greater than about 0.98 g/mL,or greater than about 1.0 g/mL. In another embodiment, the lubricatingoils of this disclosure have a finished lubricant density of from about0.8 g/mL to about 1.2 g/mL, or from about 0.81 g/mL to about 1.0 g/mL,or from about 0.82 g/mL to about 0.96 g/mL, or from about 0.83 g/mL toabout 0.92 g/mL, or from about 0.84 g/mL to about 0.9 g/mL.

In an embodiment, the lubricating oils of this disclosure have afinished lube specific heat capacity of greater than about 1.9 kJ/kg K,2.0 kJ/kg K, or greater than about 2.1 kJ/kg K, or greater than about2.2 kJ/kg K, or greater than about 2.3 kJ/kg K, or greater than about2.4 kJ/kg K, or greater than about 2.5 kJ/kg K, or greater than about2.7 kJ/kg K, or greater than about 2.9 kJ/kg K, or greater than about3.1 kJ/kg K, or greater than about 3.3 kJ/kg K, or greater than about3.5 kJ/kg K.

In an embodiment, the lubricating oils of this disclosure may encompasssolid or semi-solid lubricants, such as for example greases. Also, in anembodiment, the lubricating oils of this disclosure have an operatingtemperature range of from about 75° C. to about 110° C.

Dielectric breakdown is another important property of the lubricatingoils of this disclosure. Dielectric breakdown is the electrical stressthat a lubricating oil can withstand without breakdown. Dielectricbreakdown is determined by ASTM D877. The voltage at which breakdownoccurs (i.e., a spark passing between electrodes) is the test result.The lubricating oils of this disclosure have dielectric breakdownproperties sufficient to be safely and efficiently used in electricvehicle powertrains.

Lubricating Oil Base Stocks and Cobase Stocks

A wide range of lubricating base oils is known in the art. Lubricatingbase oils that are useful in the present disclosure are natural oils,mineral oils and synthetic oils, and unconventional oils (or mixturesthereof) can be used unrefined, refined, or rerefined (the latter isalso known as reclaimed or reprocessed oil). Unrefined oils are thoseobtained directly from a natural or synthetic source and used withoutadded purification. These include shale oil obtained directly fromretorting operations, petroleum oil obtained directly from primarydistillation, and ester oil obtained directly from an esterificationprocess. Refined oils are similar to the oils discussed for unrefinedoils except refined oils are subjected to one or more purification stepsto improve at least one lubricating oil property. One skilled in the artis familiar with many purification processes. These processes includesolvent extraction, secondary distillation, acid extraction, baseextraction, filtration, and percolation. Rerefined oils are obtained byprocesses analogous to refined oils but using an oil that has beenpreviously used as a feed stock.

Groups I, II, III, IV and V are broad base oil stock categoriesdeveloped and defined by the American Petroleum Institute (APIPublication 1509; www.API.org) to create guidelines for lubricant baseoils. Group I base stocks have a viscosity index of between about 80 to120 and contain greater than about 0.03% sulfur and/or less than about90% saturates. Group II base stocks have a viscosity index of betweenabout 80 to 120, and contain less than or equal to about 0.03% sulfurand greater than or equal to about 90% saturates. Group III stocks havea viscosity index greater than about 120 and contain less than or equalto about 0.03% sulfur and greater than about 90% saturates. Group IVincludes polyalphaolefins (PAO). Group V base stock includes base stocksnot included in Groups I-IV. The table below summarizes properties ofeach of these five groups. A base stock is typically defined as onespecifically characterized fluid of lubricating viscosity. A base oil istypically defined as one or more base stocks used in combination as afluid of lubricating viscosity.

Base Oil Properties Saturates Sulfur Viscosity Index Group I  <90 and/or >0.03% and ≥80 and <120 Group II ≥90 and ≤0.03% and ≥80 and <120 GroupIII ≥90 and ≤0.03% and ≥120 Group IV polyalphaolefins (PAO) Group V Allother base oil stocks not included in Groups I, II, III or IV

Natural oils include animal oils, vegetable oils (castor oil and lardoil, for example), and mineral oils. Animal and vegetable oilspossessing favorable thermal oxidative stability can be used. Of thenatural oils, mineral oils are preferred. Mineral oils vary widely as totheir crude source, for example, as to whether they are paraffinic,naphthenic, or mixed paraffinic-naphthenic.

Oils derived from coal or shale are also useful. Natural oils vary alsoas to the method used for their production and purification, forexample, their distillation range and whether they are straight run orcracked, hydrorefined, or solvent extracted.

Group II and/or Group III hydroprocessed or hydrocracked base stocks,including synthetic oils such as alkyl aromatics and synthetic estersare also well known base stock oils. High-quality Group II and Group IIIhydroprocessed or hydrocracked hydrocarbon base stocks (which may beknown respectively as Group II+ and Group III+) are also well known asuseful base stock oils. For example, ExxonMobil EHC™ base stocks areGroup II base stocks useful in the instant invention.

Synthetic oils include hydrocarbon oil. Hydrocarbon oils include oilssuch as polymerized and interpolymerized olefins (polybutylenes,polypropylenes, propylene isobutylene copolymers, ethylene-olefincopolymers, and ethylene-alphaolefin copolymers, for example).Polyalphaolefin (PAO) oil base stocks are commonly used synthetichydrocarbon oil. By way of example, PAOs derived from C₈, C₁₀, C₁₂, C₁₄olefins or mixtures thereof may be utilized. See U.S. Pat. Nos.4,956,122; 4,827,064; and 4,827,073.

The number average molecular weights of the PAOs, which are knownmaterials and generally available on a major commercial scale fromsuppliers such as ExxonMobil Chemical Company, Chevron Phillips ChemicalCompany, BP, and others, typically vary from about 250 to about 3,000,although PAO's may be made in viscosities up to about 150 cSt (100° C.).The PAOs are typically comprised of relatively low molecular weighthydrogenated polymers or oligomers of alphaolefins which include, butare not limited to, C₂ to about C₃₂ alphaolefins with the C₈ to aboutC₁₆ alphaolefins, such as 1-octene, 1-decene, 1-dodecene and the like,being preferred. The preferred polyalphaolefins are poly-1-octene,poly-1-decene and poly-1-dodecene and mixtures thereof and mixedolefin-derived polyolefins. However, the dimers of higher olefins in therange of C₁₄ to C₁₈ may be used to provide low viscosity base stocks ofacceptably low volatility. Depending on the viscosity grade and thestarting oligomer, the PAOs may be predominantly trimers and tetramersof the starting olefins, with minor amounts of the higher oligomers,having a viscosity range of 1.5 to 12 cSt. PAO fluids of particular usemay include 3.0 cSt, 3.4 cSt, and/or 3.6 cSt and combinations thereof.Mixtures of PAO fluids having a viscosity range of 1.5 to approximately150 cSt or more may be used if desired.

The PAO fluids may be conveniently made by the polymerization of analphaolefin in the presence of a polymerization catalyst such as theFriedel-Crafts catalysts including, for example, aluminum trichloride,boron trifluoride or complexes of boron trifluoride with water, alcoholssuch as ethanol, propanol or butanol, carboxylic acids or esters such asethyl acetate or ethyl propionate. For example the methods disclosed byU.S. Pat. No. 4,149,178 or 3,382,291 may be conveniently used herein.Other descriptions of PAO synthesis are found in the following U.S. Pat.Nos. 3,742,082; 3,769,363; 3,876,720; 4,239,930; 4,367,352; 4,413,156;4,434,408; 4,910,355; 4,956,122; and 5,068,487. The dimers of the C₁₄ toC₁₈ olefins are described in U.S. Pat. No. 4,218,330.

Other useful lubricant oil base stocks include wax isomerate base stocksand base oils, comprising hydroisomerized waxy stocks (e.g. waxy stockssuch as gas oils, slack waxes, fuels hydrocracker bottoms, etc.),hydroisomerized Fischer-Tropsch waxes, Gas-to-Liquids (GTL) base stocksand base oils, and other wax isomerate hydroisomerized base stocks andbase oils, or mixtures thereof. Fischer-Tropsch waxes, the high boilingpoint residues of Fischer-Tropsch synthesis, are highly paraffinichydrocarbons with very low sulfur content. The hydroprocessing used forthe production of such base stocks may use an amorphoushydrocracking/hydroisomerization catalyst, such as one of thespecialized lube hydrocracking (LHDC) catalysts or a crystallinehydrocracking/hydroisomerization catalyst, preferably a zeoliticcatalyst. For example, one useful catalyst is ZSM-48 as described inU.S. Pat. No. 5,075,269, the disclosure of which is incorporated hereinby reference in its entirety. Processes for makinghydrocracked/hydroisomerized distillates andhydrocracked/hydroisomerized waxes are described, for example, in U.S.Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as well as inBritish Patent Nos. 1,429,494; 1,350,257; 1,440,230 and 1,390,359. Eachof the aforementioned patents is incorporated herein in their entirety.Particularly favorable processes are described in European PatentApplication Nos. 464546 and 464547, also incorporated herein byreference. Processes using Fischer-Tropsch wax feeds are described inU.S. Pat. Nos. 4,594,172 and 4,943,672, the disclosures of which areincorporated herein by reference in their entirety.

Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived base oils,and other wax-derived hydroisomerized (wax isomerate) base oils beadvantageously used in the instant disclosure, and may have usefulkinematic viscosities at 100° C. of about 3 cSt to about 50 cSt,preferably about 3 cSt to about 30 cSt, more preferably about 3.5 cSt toabout 25 cSt, as exemplified by GTL 4 with kinematic viscosity of about4.0 cSt at 100° C. and a viscosity index of about 141. TheseGas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived base oils,and other wax-derived hydroisomerized base oils may have useful pourpoints of about −20° C. or lower, and under some conditions may haveadvantageous pour points of about −25° C. or lower, with useful pourpoints of about −30° C. to about −40° C. or lower. Useful compositionsof Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived baseoils, and wax-derived hydroisomerized base oils are recited in U.S. Pat.Nos. 6,080,301; 6,090,989, and 6,165,949 for example, and areincorporated herein in their entirety by reference.

The hydrocarbyl aromatics can be used as a base oil or base oilcomponent and can be any hydrocarbyl molecule that contains at leastabout 5% of its weight derived from an aromatic moiety such as abenzenoid moiety or naphthenoid moiety, or their derivatives. Thesehydrocarbyl aromatics include alkyl benzenes, alkyl naphthalenes, alkyldiphenyl oxides, alkyl naphthols, alkyl diphenyl sulfides, alkylatedbis-phenol A, alkylated thiodiphenol, and the like. The aromatic can bemono-alkylated, dialkylated, polyalkylated, and the like. The aromaticcan be mono- or poly-functionalized. The hydrocarbyl groups can also becomprised of mixtures of alkyl groups, alkenyl groups, alkynyl,cycloalkyl groups, cycloalkenyl groups and other related hydrocarbylgroups. The hydrocarbyl groups can range from about C₆ up to about C₆₀with a range of about C₈ to about C₂₀ often being preferred. A mixtureof hydrocarbyl groups is often preferred, and up to about three suchsubstituents may be present. The hydrocarbyl group can optionallycontain sulfur, oxygen, and/or nitrogen containing substituents. Thearomatic group can also be derived from natural (petroleum) sources,provided at least about 5% of the molecule is comprised of an above-typearomatic moiety. Viscosities at 100° C. of approximately 3 cSt to about50 cSt are preferred, with viscosities of approximately 3.4 cSt to about20 cSt often being more preferred for the hydrocarbyl aromaticcomponent. In one embodiment, an alkyl naphthalene where the alkyl groupis primarily comprised of 1-hexadecene is used. Other alkylates ofaromatics can be advantageously used. Naphthalene or methyl naphthalene,for example, can be alkylated with olefins such as octene, decene,dodecene, tetradecene or higher, mixtures of similar olefins, and thelike. Useful concentrations of hydrocarbyl aromatic in a lubricant oilcomposition can be about 2% to about 25%, preferably about 4% to about20%, and more preferably about 4% to about 15%, depending on theapplication.

Alkylated aromatics such as the hydrocarbyl aromatics of the presentdisclosure may be produced by well-known Friedel-Crafts alkylation ofaromatic compounds. See Friedel-Crafts and Related Reactions, Olah, G.A. (ed.), Inter-science Publishers, New York, 1963. For example, anaromatic compound, such as benzene or naphthalene, is alkylated by anolefin, alkyl halide or alcohol in the presence of a Friedel-Craftscatalyst. See Friedel-Crafts and Related Reactions, Vol. 2, part 1,chapters 14, 17, and 18, See Olah, G. A. (ed.), Inter-sciencePublishers, New York, 1964. Many homogeneous or heterogeneous, solidcatalysts are known to one skilled in the art. The choice of catalystdepends on the reactivity of the starting materials and product qualityrequirements. For example, strong acids such as AlCl₃, BF₃, or HF may beused. In some cases, milder catalysts such as FeCl₃ or SnCl₄ arepreferred. Newer alkylation technology uses zeolites or solid superacids.

Esters comprise a useful base stock. Additive solvency and sealcompatibility characteristics may be secured by the use of esters suchas the esters of dibasic acids with monoalkanols and the polyol estersof monocarboxylic acids. Esters of the former type include, for example,the esters of dicarboxylic acids such as phthalic acid, succinic acid,alkyl succinic acid, alkenyl succinic acid, maleic acid, azelaic acid,suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic aciddimer, malonic acid, alkyl malonic acid, alkenyl malonic acid, etc.,with a variety of alcohols such as butyl alcohol, hexyl alcohol, dodecylalcohol, 2-ethylhexyl alcohol, etc. Specific examples of these types ofesters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexylfumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate,di(2-ethylhexyl) azelate, dioctyl phthalate, didecyl phthalate,dieicosyl sebacate, etc.

Particularly useful synthetic esters are those which are obtained byreacting one or more polyhydric alcohols, preferably the hinderedpolyols (such as the neopentyl polyols, e.g., neopentyl glycol,trimethylol ethane, 2-methyl-2-propyl-1,3-propanediol, trimethylolpropane, pentaerythritol and dipentaerythritol) with alkanoic acidscontaining at least about 4 carbon atoms, preferably C₅ to C₃₀ acidssuch as saturated straight chain fatty acids including caprylic acid,capric acid, lauric acid, myristic acid, palmitic acid, stearic acid,arachic acid, and behenic acid, or the corresponding branched chainfatty acids or unsaturated fatty acids such as oleic acid, or mixturesof any of these materials.

Suitable synthetic ester components include the esters of trimethylolpropane, trimethylol butane, trimethylol ethane, pentaerythritol and/ordipentaerythritol with one or more monocarboxylic acids containing fromabout 5 to about 10 carbon atoms. These esters are widely availablecommercially, for example, the Mobil P-41 and P-51 esters of ExxonMobilChemical Company.

Also useful are esters derived from renewable material such as coconut,palm, rapeseed, soy, sunflower and the like. These esters may bemonoesters, di-esters, polyol esters, complex esters, or mixturesthereof. These esters are widely available commercially, for example,the Mobil P-51 ester of ExxonMobil Chemical Company.

Engine oil compositions containing renewable esters are included in thisdisclosure. For such compositions, the renewable content of the ester istypically greater than about 70 weight percent, preferably more thanabout 80 weight percent and most preferably more than about 90 weightpercent.

Useful base stock fluids also include polyethers, polyglycols,polyalkylene glycols (PAG), polypropanols, polyalkylene propanols,polypropylene oxides, polybutylene oxides, polytetrahydrofurans,polyalkylene tetrahydrofurans, and analogues of polyether-type fluids,where such polyethers may be uncapped, mono-capped, di-capped, ormulti-capped, with functional groups which may include for exampleethers, esters, ketones, urethanes, aromatics, heteroaromatics,hydrocarbyl moieties, etc. In addition, useful polyether-type base stockfluids include oil-soluble or hydrocarbon-soluble versions of polyethersor PAGs or polyalkylene ethers or polyalkylene oxides.

Other useful fluids of lubricating viscosity include non-conventional orunconventional base stocks that have been processed, preferablycatalytically, or synthesized to provide high performance lubricationcharacteristics.

Non-conventional or unconventional base stocks/base oils include one ormore of a mixture of base stock(s) derived from one or moreGas-to-Liquids (GTL) materials, as well as isomerate/isodewaxate basestock(s) derived from natural wax or waxy feeds, mineral and ornon-mineral oil waxy feed stocks such as slack waxes, natural waxes, andwaxy stocks such as gas oils, waxy fuels hydrocracker bottoms, waxyraffinate, hydrocrackate, thermal crackates, or other mineral, mineraloil, or even non-petroleum oil derived waxy materials such as waxymaterials received from coal liquefaction or shale oil, and mixtures ofsuch base stocks.

GTL materials are materials that are derived via one or more synthesis,combination, transformation, rearrangement, and/ordegradation/deconstructive processes from gaseous carbon-containingcompounds, hydrogen-containing compounds and/or elements as feed stockssuch as hydrogen, carbon dioxide, carbon monoxide, water, methane,ethane, ethylene, acetylene, propane, propylene, propyne, butane,butylenes, and butynes. GTL base stocks and/or base oils are GTLmaterials of lubricating viscosity that are generally derived fromhydrocarbons; for example, waxy synthesized hydrocarbons, that arethemselves derived from simpler gaseous carbon-containing compounds,hydrogen-containing compounds and/or elements as feed stocks. GTL basestock(s) and/or base oil(s) include oils boiling in the lube oil boilingrange (1) separated/fractionated from synthesized GTL materials such as,for example, by distillation and subsequently subjected to a final waxprocessing step which involves either or both of a catalytic dewaxingprocess, or a solvent dewaxing process, to produce lube oils ofreduced/low pour point; (2) synthesized wax isomerates, comprising, forexample, hydrodewaxed or hydroisomerized cat and/or solvent dewaxedsynthesized wax or waxy hydrocarbons; (3) hydrodewaxed orhydroisomerized cat and/or solvent dewaxed Fischer-Tropsch (F-T)material (i.e., hydrocarbons, waxy hydrocarbons, waxes and possibleanalogous oxygenates); preferably hydrodewaxed orhydroisomerized/followed by cat and/or solvent dewaxing dewaxed F-T waxyhydrocarbons, or hydrodewaxed or hydroisomerized/followed by cat (orsolvent) dewaxing dewaxed, F-T waxes, or mixtures thereof.

GTL base stock(s) and/or base oil(s) derived from GTL materials,especially, hydrodewaxed or hydroisomerized/followed by cat and/orsolvent dewaxed wax or waxy feed, preferably F-T material derived basestock(s) and/or base oil(s), are characterized typically as havingkinematic viscosities at 100° C. of from about 2 mm²/s to about 50 mm²/s(ASTM D445). They are further characterized typically as having pourpoints of −5° C. to about −40° C. or lower (ASTM D97). They are alsocharacterized typically as having viscosity indices of about 80 to about140 or greater (ASTM D2270).

In addition, the GTL base stock(s) and/or base oil(s) are typicallyhighly paraffinic (>90% saturates), and may contain mixtures ofmonocycloparaffins and multicycloparaffins in combination withnon-cyclic isoparaffins. The ratio of the naphthenic (i.e.,cycloparaffin) content in such combinations varies with the catalyst andtemperature used. Further, GTL base stock(s) and/or base oil(s)typically have very low sulfur and nitrogen content, generallycontaining less than about 10 ppm, and more typically less than about 5ppm of each of these elements. The sulfur and nitrogen content of GTLbase stock(s) and/or base oil(s) obtained from F-T material, especiallyF-T wax, is essentially nil. In addition, the absence of phosphorous andaromatics make this materially especially suitable for the formulatingof low SAP products.

The term GTL base stock and/or base oil and/or wax isomerate base stockand/or base oil is to be understood as embracing individual fractions ofsuch materials of wide viscosity range as recovered in the productionprocess, mixtures of two or more of such fractions, as well as mixturesof one or two or more low viscosity fractions with one, two or morehigher viscosity fractions to produce a blend wherein the blend exhibitsa target kinematic viscosity.

The GTL material, from which the GTL base stock(s) and/or base oil(s)is/are derived is preferably an F-T material (i.e., hydrocarbons, waxyhydrocarbons, wax).

Base oils for use in the lubricating oils useful in the presentdisclosure are any of the variety of oils corresponding to API Group I,Group II, Group III, Group IV, and Group V oils, and mixtures thereof,preferably API Group II, Group III, Group IV, and Group V oils, andmixtures thereof, more preferably Group III, Group IV, and Group V baseoils, and mixtures thereof. Highly paraffinic base oils can be used toadvantage in the lubricating oils useful in the present disclosure.Minor quantities of Group I stock, such as the amount used to diluteadditives for blending into lube oil products, can also be used. Even inregard to the Group II stocks, it is preferred that the Group II stockbe in the higher quality range associated with that stock, i.e. a GroupII stock having a viscosity index in the range 100<VI<120.

The base oil constitutes the major component of the engine oil lubricantcomposition of the present disclosure and typically is present in anamount ranging from about 50 to about 99 weight percent, preferably fromabout 70 to about 95 weight percent, and more preferably from about 85to about 95 weight percent, based on the total weight of thecomposition. The base oil may be selected from any of the synthetic ornatural oils typically used as crankcase lubricating oils forspark-ignited and compression-ignited engines. The base oil convenientlyhas a kinematic viscosity, according to ASTM standards, of about 2.5 cStto about 12 cSt (or mm²/s) at 100° C. and preferably of about 2.5 cSt toabout 9 cSt (or mm²/s) at 100° C. Mixtures of synthetic and natural baseoils may be used if desired. Bi-modal mixtures of Group I, II, III, IV,and/or V base stocks may be used if desired.

Antioxidants

The lubricating oil compositions include at least one antioxidant.Antioxidants retard the oxidative degradation of base oils duringservice. Such degradation may result in deposits on metal surfaces, thepresence of sludge, or a viscosity increase in the lubricant. Oneskilled in the art knows a wide variety of oxidation inhibitors that areuseful in lubricating oil compositions. See, Klamann in Lubricants andRelated Products, op cite, and U.S. Pat. Nos. 4,798,684 and 5,084,197,for example.

Illustrative antioxidants include sterically hindered alkyl phenols suchas 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol and2,6-di-tert-butyl-4-(2-octyl-3-propanoic) phenol; N,N-di(alkylphenyl)amines; and alkylated phenylenediamines.

The antioxidant may be a hindered phenolic antioxidant such as butylatedhydroxytoluene, suitably present in an amount of 0.01 to 5%, preferably0.4 to 0.8%, by weight of the lubricant composition. Alternatively, orin addition, the antioxidant may comprise an aromatic amine antioxidantsuch as mono-octylphenylalphanapthyl amine or p,p-dioctyldiphenylamine,used singly or in admixture. The amine antioxidant component is suitablypresent in a range of from 0.01 to 5% by weight of the lubricantcomposition, more preferably 0.5 to 1.5%.

Useful antioxidants include hindered phenols. These phenolicantioxidants may be ashless (metal-free) phenolic compounds or neutralor basic metal salts of certain phenolic compounds. Typical phenolicantioxidant compounds are the hindered phenolics which are the oneswhich contain a sterically hindered hydroxyl group, and these includethose derivatives of dihydroxy aryl compounds in which the hydroxylgroups are in the o- or p-position to each other. Typical phenolicantioxidants include the hindered phenols substituted with C₆+ alkylgroups and the alkylene coupled derivatives of these hindered phenols.Examples of phenolic materials of this type 2-t-butyl-4-heptyl phenol;2-t-butyl-4-octyl phenol; 2-t-butyl-4-dodecyl phenol;2,6-di-t-butyl-4-heptyl phenol; 2,6-di-t-butyl-4-dodecyl phenol;2-methyl-6-t-butyl-4-heptyl phenol; and 2-methyl-6-t-butyl-4-dodecylphenol. Other useful hindered mono-phenolic antioxidants may include forexample hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.Bis-phenolic antioxidants may also be advantageously used in combinationwith the instant disclosure. Examples of ortho-coupled phenols include:2,2′-bis(4-heptyl-6-t-butyl-phenol); 2,2′-bis(4-octyl-6-t-butyl-phenol);and 2,2′-bis(4-dodecyl-6-t-butyl-phenol). Para-coupled bisphenolsinclude for example 4,4′-bis(2,6-di-t-butyl phenol) and4,4′-methylene-bis(2,6-di-t-butyl phenol).

Other illustrative phenolic antioxidants include sulfurized andnon-sulfurized phenolic antioxidants. The terms “phenolic type” or“phenolic antioxidant” used herein includes compounds having one or morethan one hydroxyl group bound to an aromatic ring which may itself bemononuclear, e.g., benzyl, or poly-nuclear, e.g., naphthyl and Spiroaromatic compounds. Thus “phenol type” includes phenol per se, catechol,resorcinol, hydroquinone, naphthol, etc., as well as alkyl or alkenyland sulfurized alkyl or alkenyl derivatives thereof, and bisphenol typecompounds including such bi-phenol compounds linked by alkylene bridgessulfuric bridges or oxygen bridges. Alkyl phenols include mono- andpoly-alkyl or alkenyl phenols, the alkyl or alkenyl group containingfrom 3-100 carbons, preferably 4 to 50 carbons and sulfurizedderivatives thereof, the number of alkyl or alkenyl groups present inthe aromatic ring ranging from 1 to up to the available unsatisfiedvalences of the aromatic ring remaining after counting the number ofhydroxyl groups bound to the aromatic ring.

Generally, therefore, the phenolic antioxidant may be represented by thegeneral formula:

(R)_(x)—Ar—(OH)_(y)

where Ar is selected from the group consisting of:

wherein R is a C₃-C₁₀₀ alkyl or alkenyl group, a sulfur substitutedalkyl or alkenyl group, preferably a C₄-C₅₀ alkyl or alkenyl group orsulfur substituted alkyl or alkenyl group, more preferably C₃-C₁₀₀ alkylor sulfur substituted alkyl group, most preferably a C₄-C₅₀ alkyl group,R^(g) is a C₁-C₁₀₀ alkylene or sulfur substituted alkylene group,preferably a C₂-050 alkylene or sulfur substituted alkylene group, morepreferably a C₂-C₂₀ alkylene or sulfur substituted alkylene group, y isat least 1 to up to the available valences of Ar, x ranges from 0 to upto the available valances of Ar-y, z ranges from 1 to 10, n ranges from0 to 20, and m is 0 to 4 and p is 0 or 1, preferably y ranges from 1 to3, x ranges from 0 to 3, z ranges from 1 to 4 and n ranges from 0 to 5,and p is 0.

Preferred phenolic antioxidant compounds are the hindered phenolics andphenolic esters which contain a sterically hindered hydroxyl group, andthese include those derivatives of dihydroxy aryl compounds in which thehydroxyl groups are in the o- or p-position to each other. Typicalphenolic antioxidants include the hindered phenols substituted withC.sub.1+ alkyl groups and the alkylene coupled derivatives of thesehindered phenols. Examples of phenolic materials of this type2-t-butyl-4-heptyl phenol; 2-t-butyl-4-octyl phenol; 2-t-butyl-4-dodecylphenol; 2,6-di-t-butyl-4-heptyl phenol; 2,6-di-t-butyl-4-dodecyl phenol;2-methyl-6-t-butyl-4-heptyl phenol; 2-methyl-6-t-butyl-4-dodecyl phenol;2,6-di-t-butyl-4 methyl phenol; 2,6-di-t-butyl-4-ethyl phenol; and2,6-di-t-butyl 4 alkoxy phenol; and

Phenolic type antioxidants are well known in the lubricating industryand commercial examples such as Ethanox™ 1710, Irganox™ 1076, Irganox™L1035, Irganox™ 1010, Irganox™ L109, Irganox™ L118, Irganox™ L135 andthe like are familiar to those skilled in the art. The above ispresented only by way of exemplification, not limitation on the type ofphenolic antioxidants which can be used.

Other examples of phenol-based antioxidants include 2-t-butylphenol,2-t-butyl-4-methylphenol, 2-t-butyl-5-methylphenol,2,4-di-t-butylphenol, 2,4-dimethyl-6-t-butylphenol,2-t-butyl-4-methoxyphenol, 3-t-butyl-4-methoxyphenol,2,5-di-t-butylhydroquinone (manufactured by the Kawaguchi Kagaku Co.under trade designation “Antage DBH”), 2,6-di-t-butylphenol and2,6-di-t-butyl-4-alkylphenols such as 2,6-di-t-butyl-4-methylphenol and2,6-di-t-butyl-4-ethylphenol; 2,6-di-t-butyl-4-alkoxyphenols such as2,6-di-t-butyl-4-methoxyphenol and 2,6-di-t-butyl-4-ethoxyphenol,3,5-di-t-butyl-4-hydroxybenzylmercaptoocty-1 acetate,alkyl-3-(3,5-di-t-11) butyl-4-hydroxyphenyl)propionates such asn-octyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured bythe Yoshitomi Seiyaku Co. under the trade designation “Yonox SS”),n-dodecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and2′-ethylhexyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate;2,6-di-t-butyl-alpha-dimethylamino-p-cresol,2,2′-methylenebis(4-alkyl-6-t-butylphenol) compounds such as2,2′-methylenebis(4-methyl-6-t-butylphenol) (manufactured by theKawaguchi Kagaku Co. under the trade designation “Antage W-400”) and2,2′-methylenebis(4-ethyl-6-t-butylphenol) (manufactured by theKawaguchi Kagaku Co. under the trade designation “Antage W-500”);bisphenols such as 4,4′-butylidenebis(3-methyl-6-t-butyl-phenol)(manufactured by the Kawaguchi Kagaku Co. under the trade designation“Antage W-300”), 4,4′-methylenebis(2,6-di-t-butylphenol) (manufacturedby Laporte Performance Chemicals under the trade designation “Ionox220AH”), 4,4′-bis(2,6-di-t-butylphenol), 2,2-(di-p-hydroxyphenyl)propane(Bisphenol A), 2,2-bis(3,5-di-t-butyl-4-hydroxyphenyl)propane,4,4′-cyclohexylidenebis(2,6-di-t-butylphenol), hexamethylene glycolbis[3, (3,5-di-t-butyl-4-hydroxyphenyl)propionate] (manufactured by theCiba Speciality Chemicals Co. under the trade designation “IrganoxL109”), triethylene glycolbis[3-(3-t-butyl-4-hydroxy-y-5-methylphenyl)propionate] (manufactured bythe Yoshitomi Seiyaku Co. under the trade designation “Tominox 917”),2,2′-thio[diethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate](manufactured by the Ciba Speciality Chemicals Co. under the tradedesignation “Irganox L115”),3,9-bis{1,1-dimethyl-2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)-propionyloxy]ethyl}2,4,8,10-tetraoxaspiro[5,5]undecane(manufactured by the Sumitomo Kagaku Co. under the trade designation“Sumilizer GA80”) and 4,4′-thiobis(3-methyl-6-t-butylphenol)(manufactured by the Kawaguchi Kagaku Co. under the trade designation“Antage RC”), 2,2′-thiobis(4,6-di-t-butylresorcinol); polyphenols suchastetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionato[methane(manufactured by the Ciba Speciality Chemicals Co. under the tradedesignation “Irganox L101”),1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl-1)butane (manufactured bythe Yoshitomi Seiyaku Co. under the trade designation “Yoshinox 930”),1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene(manufactured by Ciba Speciality Chemicals under the trade designation“Irganox 330”), bis[3,3′-bis(4′-hydroxy-3′-t-butylphenyl)butyric acid]glycol ester,2-(3′,5′-di-t-butyl-4-hydroxyphenyl)-methyl-4-(2″,4″-di-t-butyl-3″-hydroxyphenyl)methyl-6-t-butylphenoland 2,6-bis(2′-hydroxy-3′-t-butyl-5′-methylbenzyl)-4-methylphenol; andphenol/aldehyde condensates such as the condensates of p-t-butylphenoland formaldehyde and the condensates of p-t-butylphenol andacetaldehyde.

Effective amounts of one or more catalytic antioxidants may also beused. The catalytic antioxidants comprise an effective amount of a) oneor more oil soluble polymetal organic compounds; and, effective amountsof b) one or more substituted N,N′-diaryl-o-phenylenediamine compoundsor c) one or more hindered phenol compounds; or a combination of both b)and c). Catalytic antioxidants are more fully described in U.S. Pat. No.8,048,833, herein incorporated by reference in its entirety.

Illustrative aromatic amine antioxidants include phenyl-alpha-naphthylamine which is described by the following molecular structure:

wherein R^(z) is hydrogen or a C₁ to C₁₄ linear or C₃ to C₁₄ branchedalkyl group, preferably C₁ to C₁₀ linear or C₃ to Cm branched alkylgroup, more preferably linear or branched C₆ to C₈ and n is an integerranging from 1 to 5 preferably 1. A particular example is Irganox L06.

Other aromatic amine antioxidants include other alkylated andnon-alkylated aromatic amines such as aromatic monoamines.

Typical aromatic amines antioxidants have alkyl substituent groups of atleast 6 carbon atoms. Examples of aliphatic groups include hexyl,heptyl, octyl, nonyl, and decyl. Generally, the aliphatic groups willnot contain more than 14 carbon atoms. The general types of such otheradditional amine antioxidants which may be present includediphenylamines, phenothiazines, imidodibenzyls and diphenyl phenylenediamines. Mixtures of two or more of such other additional aromaticamines may also be present. Polymeric amine antioxidants can also beused.

The antioxidants or oxidation inhibitors that are useful in lubricantoil compositions of the disclosure are the hindered phenols (e.g.,2,6-di-(t-butyl)phenol); aromatic amines (e.g., alkylated diphenylamines); alkyl polysulfides; selenides; borates (e.g., epoxide/boricacid reaction products); phosphorodithioic acids, esters and/or salts;and the dithiocarbamate (e.g., zinc dithiocarbamates). In an embodiment,these antioxidants or oxidation inhibitors can be employed at ratios ofamine/phenolic from 1:10 to 10:1 of the mixtures preferred.

The antioxidants or oxidation inhibitors that are also useful inlubricant oil compositions of the disclosure are chlorinated aliphatichydrocarbons such as chlorinated wax; organic sulfides and polysulfidessuch as benzyl disulfide, bis(chlorobenzyl)disulfide, dibutyltetrasulfide, sulfurized methyl ester of oleic acid, sulfurizedalkylphenol, sulfurized dipentene, and sulfurized terpene;phosphosulfiirized hydrocarbons such as the reaction product of aphosphorus sulfide with turpentine or methyl oleate, phosphorus estersincluding principally dihydrocarbon and trihydrocarbon phosphites suchas dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite,pentylphenyl phosphite, dipentylphenyl phosphite, tridecyl phosphite,distearyl phosphite, dimethyl naphthyl phosphite, oleyl 4-pentylphenylphosphite, polypropylene (molecular weight 500)-substituted phenylphosphite, diisobutyl-substituted phenyl phosphite; metalthiocarbamates, such as zinc dioctyldithiocarbamate, and bariumheptylphenyl dithiocarbamate; Group II metal phosphorodithioates such aszinc dicyclohexylphosphorodithioate, zinc dioctylphosphorodithioate,barium di(heptylphenyl)(phosphorodithioate, cadmiumdinonylphosphorodithioate, and the reaction of phosphorus pentasulfidewith an equimolar mixture of isopropyl alcohol, 4-methyl-2-pentanol, andn-hexyl alcohol.

Oxidation inhibitors including organic compounds containing sulfur,nitrogen, phosphorus and some alkylphenols are useful additives in thelubricating oil compositions of this disclosure. Two general types ofoxidation inhibitors are those that react with the initiators, peroxyradicals, and hydroperoxides to form inactive compounds, and those thatdecompose these materials to form less active compounds. Examples arehindered (alkylated) phenols, e.g.6-di(tert-butyl)-4-methyl-phenol[2,6-di(tert-butyl)-p-cresol, DBPC], andaromatic amines, e.g. N-phenyl-alpha-naphthalamine.

Sulfurized alkyl phenols and alkali or alkaline earth metal saltsthereof also are useful antioxidants.

Another class of antioxidant used in lubricating oil compositions andwhich may also be present are oil-soluble copper compounds. Anyoil-soluble suitable copper compound may be blended into the lubricatingoil. Examples of suitable copper antioxidants include copperdihydrocarbyl thio- or dithio-phosphates and copper salts of carboxylicacid (naturally occurring or synthetic). Other suitable copper saltsinclude copper dithiacarbamates, sulphonates, phenates, andacetylacetonates. Basic, neutral, or acidic copper Cu(I) and or Cu(II)salts derived from alkenyl succinic acids or anhydrides are known to beparticularly useful.

A sulfur-containing antioxidant may be any and every antioxidantcontaining sulfur, for example, including dialkyl thiodipropionates suchas dilauryl thiodipropionate and distearyl thiodipropionate,dialkyldithiocarbamic acid derivatives (excluding metal salts),bis(3,5-di-t-butyl-4-hydroxybenzyl)sulfide, mercaptobenzothiazole,reaction products of phosphorus pentoxide and olefins, and dicetylsulfide. Of these, preferred are dialkyl thiodipropionates such asdilauryl thiodipropionate and distearyl thiodipropionate. The amine-typeantioxidant includes, for example, monoalkyldiphenylamines such asmonooctyldiphenylamine and monononyldiphenyl amine;dialkyldiphenylamines such as 4,4′-dibutyldiphenylamine,4,4′-dipentyldiphenylamine, 4,4′-dihexyldiphenylamine,4,4′-diheptyldiphenylamine, 4,4′-dioctyldiphenylamine and4,4′-dinonyldiphenylamine; polyalkyldiphenylamines such astetrabutyldiphenylamine, tetrahexyldiphenylamine,tetraoctyldiphenylamine and tetranonyldiphenylamine; and naphthylaminessuch as alpha-naphthylamine, phenyl-alpha-naphthylamine,butylphenyl-alpha-naphthylamine, pentylphenyl-alpha-naphthylamine,hexylphenyl-alpha-naphthylamine, heptylphenyl-alpha-naphthylamine,octylphenyl-alpha-naphthyl amine and nonylphenyl-alpha-naphthylamine. Ofthese, preferred are dialkyldiphenylamines.

Examples of sulfur-based antioxidants include dialkylsulfides such asdidodecylsulfide and dioctadecylsulfide; thiodipropionic acid esterssuch as didodecyl thiodipropionate, dioctadecyl thiodipropionate,dimyristyl thiodipropionate and dodecyloctadecyl thiodipropionate, and2-mercaptobenzimidazole.

Such antioxidants may be used individually or as mixtures of one or moretypes of antioxidants, the total amount employed being an amount ofabout 0.01 to about 5 wt %, preferably 0.1 to about 4.5 wt %, morepreferably 0.25 to 3 wt % (on an as-received basis).

Detergents

The lubricating oil compositions include at least one detergent.Illustrative detergents useful in this disclosure include, for example,alkali metal detergents, alkaline earth metal detergents, or mixtures ofone or more alkali metal detergents and one or more alkaline earth metaldetergents. A typical detergent is an anionic material that contains along chain hydrophobic portion of the molecule and a smaller anionic oroleophobic hydrophilic portion of the molecule. The anionic portion ofthe detergent is typically derived from an organic acid such as a sulfuracid, carboxylic acid (e.g., salicylic acid), phosphorous acid, phenol,or mixtures thereof. The counterion is typically an alkaline earth oralkali metal.

The detergent is preferably a metal salt of an organic or inorganicacid, a metal salt of a phenol, or mixtures thereof. The metal ispreferably selected from an alkali metal, an alkaline earth metal, andmixtures thereof. The organic or inorganic acid is selected from analiphatic organic or inorganic acid, a cycloaliphatic organic orinorganic acid, an aromatic organic or inorganic acid, and mixturesthereof.

The metal is preferably selected from an alkali metal, an alkaline earthmetal, and mixtures thereof. More preferably, the metal is selected fromcalcium (Ca), magnesium (Mg), and mixtures thereof.

The organic acid or inorganic acid is preferably selected from a sulfuracid, a carboxylic acid, a phosphorus acid, and mixtures thereof.

Preferably, the metal salt of an organic or inorganic acid or the metalsalt of a phenol comprises calcium phenate, calcium sulfonate, calciumsalicylate, magnesium phenate, magnesium sulfonate, magnesiumsalicylate, and mixtures thereof.

Salts that contain a substantially stochiometric amount of the metal aredescribed as neutral salts and have a total base number (TBN, asmeasured by ASTM D2896) of from 0 to 80. Many compositions areoverbased, containing large amounts of a metal base that is achieved byreacting an excess of a metal compound (a metal hydroxide or oxide, forexample) with an acidic gas (such as carbon dioxide). Useful detergentscan be neutral, mildly overbased, or highly overbased. These detergentscan be used in mixtures of neutral, overbased, highly overbased calciumsalicylate, sulfonates, phenates and/or magnesium salicylate,sulfonates, phenates. The TBN ranges can vary from low, medium to highTBN products, including as low as 0 to as high as 600. Preferably theTBN delivered by the detergent is between 1 and 20. More preferablybetween 1 and 12. Mixtures of low, medium, high TBN can be used, alongwith mixtures of calcium and magnesium metal based detergents, andincluding sulfonates, phenates, salicylates, and carboxylates. Adetergent mixture with a metal ratio of 1, in conjunction of a detergentwith a metal ratio of 2, and as high as a detergent with a metal ratioof 5, can be used. Borated detergents can also be used.

Alkaline earth phenates are another useful class of detergent. Thesedetergents can be made by reacting alkaline earth metal hydroxide oroxide (CaO, Ca(OH)₂, BaO, Ba(OH)₂, MgO, Mg(OH)₂, for example) with analkyl phenol or sulfurized alkylphenol. Useful alkyl groups includestraight chain or branched C₁-C₃₀ alkyl groups, preferably, C₄-C₂₀ ormixtures thereof. Examples of suitable phenols include isobutylphenol,2-ethylhexylphenol, nonylphenol, dodecyl phenol, and the like. It shouldbe noted that starting alkylphenols may contain more than one alkylsubstituent that are each independently straight chain or branched andcan be used from 0.5 to 6 weight percent. When a non-sulfurizedalkylphenol is used, the sulfurized product may be obtained by methodswell known in the art. These methods include heating a mixture ofalkylphenol and sulfurizing agent (including elemental sulfur, sulfurhalides such as sulfur dichloride, and the like) and then reacting thesulfurized phenol with an alkaline earth metal base.

Metal salts of carboxylic acids are useful detergents. These carboxylicacid detergents may be prepared by reacting a basic metal compound withat least one carboxylic acid and removing free water from the reactionproduct. Detergents made from salicylic acid are one preferred class ofdetergents derived from carboxylic acids. Useful salicylates includelong chain alkyl salicylates. One useful family of compositions is ofthe formula

where R is an alkyl group having 1 to about 30 carbon atoms, n is aninteger from 1 to 4, and M is an alkaline earth metal. Preferred Rgroups are alkyl chains of at least C₁₁, preferably C₁₃ or greater. Rmay be optionally substituted with substituents that do not interferewith the detergent's function. M is preferably, calcium, magnesium, orbarium. More preferably, M is calcium.

Hydrocarbyl-substituted salicylic acids may be prepared from phenols bythe Kolbe reaction (see U.S. Pat. No. 3,595,791). The metal salts of thehydrocarbyl-substituted salicylic acids may be prepared by doubledecomposition of a metal salt in a polar solvent such as water oralcohol.

Alkaline earth metal phosphates are also used as detergents and areknown in the art.

Detergents may be simple detergents or what is known as hybrid orcomplex detergents. The latter detergents can provide the properties oftwo detergents without the need to blend separate materials. See U.S.Pat. No. 6,034,039.

Illustrative detergents include calcium alkylsalicylates, calciumalkylphenates and calcium alkarylsulfonates with alternate metal ionsused such as magnesium, barium, or sodium. Examples of the cleaning anddispersing agents which can be used include metal-based detergents suchas the neutral and basic alkaline earth metal sulphonates, alkalineearth metal phenates and alkaline earth metal salicylatesalkenylsuccinimide and alkenylsuccinimide esters and their borohydrides,phenates, salienius complex detergents and ashless dispersing agentswhich have been modified with sulfur compounds. These agents can beadded and used individually or in the form of mixtures, conveniently inan amount within the range of from 0.01 to 1 part by weight per 100parts by weight of base oil; these can also be high TBN, low TBN, ormixtures of high/low TBN.

Preferred detergents include calcium sulfonates, magnesium sulfonates,calcium salicylates, magnesium salicylates, calcium phenates, magnesiumphenates, and other related components (including borated detergents),and mixtures thereof. Preferred mixtures of detergents include magnesiumsulfonate and calcium salicylate, magnesium sulfonate and calciumsulfonate, magnesium sulfonate and calcium phenate, calcium phenate andcalcium salicylate, calcium phenate and calcium sulfonate, calciumphenate and magnesium salicylate, calcium phenate and magnesium phenate.

The detergent concentration in the lubricating oils of this disclosurecan range from about 0.01 to about 10 weight percent, preferably about0.1 to 7.5 weight percent, and more preferably from about 0.5 weightpercent to about 5 weight percent, based on the total weight of thelubricating oil.

As used herein, the detergent concentrations are given on an “asdelivered” basis. Typically, the active detergent is delivered with aprocess oil. The “as delivered” detergent typically contains from about20 weight percent to about 100 weight percent, or from about 40 weightpercent to about 60 weight percent, of active detergent in the “asdelivered” detergent product.

Dispersants

The lubricating oil compositions include at least one dispersant. Duringengine operation, oil-insoluble oxidation byproducts are produced.Dispersants help keep these byproducts in solution, thus diminishingtheir deposition on metal surfaces. Dispersants used in the formulatingof the lubricating oil may be ashless or ash-forming in nature.Preferably, the dispersant is ashless. So called ashless dispersants areorganic materials that form substantially no ash upon combustion. Forexample, non-metal-containing or borated metal-free dispersants areconsidered ashless.

Suitable dispersants typically contain a polar group attached to arelatively high molecular weight hydrocarbon chain. The polar grouptypically contains at least one element of nitrogen, oxygen, orphosphorus. Typical hydrocarbon chains contain 50 to 400 carbon atoms.

A particularly useful class of dispersants are the (poly)alkenylsuccinicderivatives, typically produced by the reaction of a long chainhydrocarbyl substituted succinic compound, usually a hydrocarbylsubstituted succinic anhydride, with a polyhydroxy or polyaminocompound. The long chain hydrocarbyl group constituting the oleophilicportion of the molecule which confers solubility in the oil, is normallya polyisobutylene group. Many examples of this type of dispersant arewell known commercially and in the literature. Exemplary U.S. patentsdescribing such dispersants are U.S. Pat. Nos. 3,172,892; 3,2145,707;3,219,666; 3,316,177; 3,341,542; 3,444,170; 3,454,607; 3,541,012;3,630,904; 3,632,511; 3,787,374 and 4,234,435. Other types of dispersantare described in U.S. Pat. Nos. 3,036,003; 3,200,107; 3,254,025;3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,413,347; 3,697,574;3,725,277; 3,725,480; 3,726,882; 4,454,059; 3,329,658; 3,449,250;3,519,565; 3,666,730; 3,687,849; 3,702,300; 4,100,082; 5,705,458. Afurther description of dispersants may be found, for example, inEuropean Patent Application No. 471 071, to which reference is made forthis purpose.

Hydrocarbyl-substituted succinic acid and hydrocarbyl-substitutedsuccinic anhydride derivatives are useful dispersants. In particular,succinimide, succinate esters, or succinate ester amides prepared by thereaction of a hydrocarbon-substituted succinic acid compound preferablyhaving at least 50 carbon atoms in the hydrocarbon substituent, with atleast one equivalent of an alkylene amine are particularly useful.

Succinimides are formed by the condensation reaction between hydrocarbylsubstituted succinic anhydrides and amines. Molar ratios can varydepending on the polyamine. For example, the molar ratio of hydrocarbylsubstituted succinic anhydride to TEPA can vary from about 1:1 to about5:1. Representative examples are shown in U.S. Pat. Nos. 3,087,936;3,172,892; 3,219,666; 3,272,746; 3,322,670; and U.S. Pat. Nos.3,652,616, 3,948,800.

Succinate esters are formed by the condensation reaction betweenhydrocarbyl substituted succinic anhydrides and alcohols or polyols.Molar ratios can vary depending on the alcohol or polyol used. Forexample, the condensation product of a hydrocarbyl substituted succinicanhydride and pentaerythritol is a useful dispersant.

Succinate ester amides are formed by condensation reaction betweenhydrocarbyl substituted succinic anhydrides and alkanol amines. Forexample, suitable alkanol amines include ethoxylatedpolyalkylpolyamines, propoxylated polyalkylpolyamines andpolyalkenylpolyamines such as polyethylene polyamines. One example ispropoxylated hexamethylenediamine. Representative examples are shown inU.S. Pat. No. 4,426,305.

The molecular weight of the hydrocarbyl substituted succinic anhydridesused in the preceding paragraphs will typically range between 800 and2,500 or more. The above products can be post-reacted with variousreagents such as sulfur, oxygen, formaldehyde, carboxylic acids such asoleic acid. The above products can also be post reacted with boroncompounds such as boric acid, borate esters or highly borateddispersants, to form borated dispersants generally having from about 0.1to about 5 moles of boron per mole of dispersant reaction product.Further, metal modified versions of the above succinic deriveddispersants are known, with illustrative examples that includezinc-modified alkyl succinimide types.

Mannich base dispersants are made from the reaction of alkylphenols,formaldehyde, and amines. See U.S. Pat. No. 4,767,551, which isincorporated herein by reference. Process aids and catalysts, such asoleic acid and sulfonic acids, can also be part of the reaction mixture.Molecular weights of the alkylphenols range from 800 to 2,500.Representative examples are shown in U.S. Pat. Nos. 3,697,574;3,703,536; 3,704,308; 3,751,365; 3,756,953; 3,798,165; and 3,803,039.

Typical high molecular weight aliphatic acid modified Mannichcondensation products useful in this disclosure can be prepared fromhigh molecular weight alkyl-substituted hydroxyaromatics or HNR₂group-containing reactants.

Hydrocarbyl substituted amine ashless dispersant additives are wellknown to one skilled in the art; see, for example, U.S. Pat. Nos.3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209, and 5,084,197.

Illustrative dispersants include borated and non-borated succinimides,including those derivatives from mono-succinimides, bis-succinimides,and/or mixtures of mono- and bis-succinimides, wherein the hydrocarbylsuccinimide is derived from a hydrocarbylene group such aspolyisobutylene having a Mn of from about 500 to about 5000, or fromabout 1000 to about 3000, or about 1000 to about 2000, or a mixture ofsuch hydrocarbylene groups, often with high terminal vinylic groups.Other preferred dispersants include succinic acid-esters and amides,alkylphenol-polyamine-coupled Mannich adducts, their capped derivatives,and other related components.

Polymethacrylate or polyacrylate derivatives are another class ofdispersants. These dispersants are typically prepared by reacting anitrogen containing monomer and a methacrylic or acrylic acid esterscontaining 5-25 carbon atoms in the ester group. Representative examplesare shown in U.S. Pat. Nos. 2,100,993, and 6,323,164. Polymethacrylateand polyacrylate dispersants are normally used as multifunctionalviscosity modifiers. The lower molecular weight versions can be used aslubricant dispersants or fuel detergents.

Other illustrative dispersants useful in this disclosure include thosederived from polyalkenyl-substituted mono- or dicarboxylic acid,anhydride or ester, which dispersant has a polyalkenyl moiety with anumber average molecular weight of at least 900 and from greater than1.3 to 1.7, preferably from greater than 1.3 to 1.6, most preferablyfrom greater than 1.3 to 1.5, functional groups (mono- or dicarboxylicacid producing moieties) per polyalkenyl moiety (a medium functionalitydispersant). Functionality (F) can be determined according to thefollowing formula:

F=(SAP×M _(n))/((112,200×A.I.)−(SAP×98))

wherein SAP is the saponification number (i.e., the number of milligramsof KOH consumed in the complete neutralization of the acid groups in onegram of the succinic-containing reaction product, as determinedaccording to ASTM D94); M_(n) is the number average molecular weight ofthe starting olefin polymer; and A.I. is the percent active ingredientof the succinic-containing reaction product (the remainder beingunreacted olefin polymer, succinic anhydride and diluent).

The polyalkenyl moiety of the dispersant may have a number averagemolecular weight of at least 900, suitably at least 1500, preferablybetween 1800 and 3000, such as between 2000 and 2800, more preferablyfrom about 2100 to 2500, and most preferably from about 2200 to about2400. The molecular weight of a dispersant is generally expressed interms of the molecular weight of the polyalkenyl moiety. This is becausethe precise molecular weight range of the dispersant depends on numerousparameters including the type of polymer used to derive the dispersant,the number of functional groups, and the type of nucleophilic groupemployed.

Polymer molecular weight, specifically M_(n), can be determined byvarious known techniques. One convenient method is gel permeationchromatography (GPC), which additionally provides molecular weightdistribution information (see W. W. Yau, J. J. Kirkland and D. D. Bly,“Modern Size Exclusion Liquid Chromatography”, John Wiley and Sons, NewYork, 1979). Another useful method for determining molecular weight,particularly for lower molecular weight polymers, is vapor pressureosmometry (e.g., ASTM D3592).

The polyalkenyl moiety in a dispersant preferably has a narrow molecularweight distribution (MWD), also referred to as polydispersity, asdetermined by the ratio of weight average molecular weight (M_(w)) tonumber average molecular weight (M_(n)). Polymers having a M_(w)/M_(n)of less than 2.2, preferably less than 2.0, are most desirable. Suitablepolymers have a polydispersity of from about 1.5 to 2.1, preferably fromabout 1.6 to about 1.8.

Suitable polyalkenes employed in the formation of the dispersantsinclude homopolymers, interpolymers or lower molecular weighthydrocarbons. One family of such polymers comprise polymers of ethyleneand/or at least one C₃ to C₂₄ alpha-olefin. Preferably, such polymerscomprise interpolymers of ethylene and at least one alpha-olefin of theabove formula.

Another useful class of polymers is polymers prepared by cationicpolymerization of monomers such as isobutene and styrene. Commonpolymers from this class include polyisobutenes obtained bypolymerization of a C₄ refinery stream having a butene content of 35 to75% by wt., and an isobutene content of 30 to 60% by wt. A preferredsource of monomer for making poly-n-butenes is petroleum feedstreamssuch as Raffinate II. These feedstocks are disclosed in the art such asin U.S. Pat. No. 4,952,739. A preferred embodiment utilizespolyisobutylene prepared from a pure isobutylene stream or a Raffinate Istream to prepare reactive isobutylene polymers with terminal vinylideneolefins. Polyisobutene polymers that may be employed are generally basedon a polymer chain of from 1500 to 3000.

Dispersants that contain the alkenyl or alkyl group have an M_(n) valueof about 500 to about 5000 and an M_(w)/M_(n) ratio of about 1 to about5. The preferred M_(n) intervals depend on the chemical nature of theagent improving filterability. Polyolefinic polymers suitable for thereaction with maleic anhydride or other acid materials or acid formingmaterials, include polymers containing a predominant quantity of C₂ toC₅ monoolefins, for example, ethylene, propylene, butylene, isobutyleneand pentene. A highly suitable polyolefinic polymer is polyisobutene.The succinic anhydride preferred as a reaction substance is PIBSA, thatis, polyisobutenyl succinic anhydride.

If the dispersant contains a succinimide comprising the reaction productof a succinic anhydride with a polyamine, the alkenyl or alkylsubstituent of the succinic anhydride serving as the reaction substanceconsists preferably of polymerised isobutene having an M_(n) value ofabout 1200 to about 2500. More advantageously, the alkenyl or alkylsubstituent of the succinic anhydride serving as the reaction substanceconsists in a polymerised isobutene having an M_(n) value of about 2100to about 2400. If the agent improving filterability contains an ester ofsuccinic acid comprising the reaction product of a succinic anhydrideand an aliphatic polyhydric alcohol, the alkenyl or alkyl substituent ofthe succinic anhydride serving as the reaction substance consistsadvantageously of a polymerised isobutene having an M_(n) value of 500to 1500. In preference, a polymerised isobutene having an M_(n) value of850 to 1200 is used.

The amides may be amides of mono- or polycarboxylic acids or reactivederivatives thereof. The amides may be characterized by a hydrocarbylgroup containing from about 6 to about 90 carbon atoms; each isindependently hydrogen or a hydrocarbyl, aminohydrocarbyl,hydroxyhydrocarbyl or a heterocyclic-substituted hydrocarbyl group,provided that both are not hydrogen; each is, independently, ahydrocarbylene group containing up to about 10 carbon atoms.

The amide can be derived from a monocarboxylic acid, a hydrocarbyl groupcontaining from 6 to about 30 or 38 carbon atoms and more often will bea hydrocarbyl group derived from a fatty acid containing from 12 toabout 24 carbon atoms.

An illustrative amide that is derived from a di- or tricarboxylic acid,will contain from 6 to about 90 or more carbon atoms depending on thetype of polycarboxylic acid. For example, when the amide is derived froma dimer acid, will contain from about 18 to about 44 carbon atoms ormore, and amides derived from trimer acids generally will contain anaverage of from about 44 to about 90 carbon atoms. Each is independentlyhydrogen or a hydrocarbyl, aminohydrocarbyl, hydroxyhydrocarbyl or aheterocyclic-substituted hydrocarbon group containing up to about 10carbon atoms. It may be independently heterocyclic substitutedhydrocarbyl groups wherein the heterocyclic substituent is derived frompyrrole, pyrroline, pyrrolidine, morpholine, piperazine, piperidine,pyridine, pipecoline, etc. Specific examples include methyl, ethyl,n-propyl, n-butyl, n-hexyl, hydroxymethyl, hydroxyethyl, hydroxypropyl,amino-methyl, aminoethyl, aminopropyl, 2-ethylpyridine,1-ethylpyrrolidine, 1-ethylpiperidine, etc.

Illustrative aliphatic monoamines include mono-aliphatic anddi-aliphatic-substituted amines wherein the aliphatic groups may besaturated or unsaturated and straight chain or branched chain. Suchamines include, for example, mono- and di-alkyl-substituted amines,mono- and dialkenyl-substituted amines, etc. Specific examples of suchmonoamines include ethyl amine, diethyl amine, n-butyl amine, di-n-butylamine, isobutyl amine, coco amine, stearyl amine, oleyl amine, etc. Anexample of a cycloaliphatic-substituted aliphatic amine is2-(cyclohexyl)-ethyl amine. Examples of heterocyclic-substitutedaliphatic amines include 2-(2-aminoethyl)-pyrrole,2-(2-aminoethyl)-1-methylpyrrole, 2-(2-aminoethyl)-1-methylpyrrolidineand 4-(2-aminoethyl)morpholine, 1-(2-aminoethyl)piperazine,1-(2-aminoethyl)piperidine, 2-(2-aminoethyl)pyridine,1-(2-aminoethyl)pyrrolidine, 1-(3-aminopropyl)imidazole,3-(2-aminopropyl)indole, 4-(3-aminopropyl)morpholine,1-(3-aminopropyl)-2-pipecoline, 1-(3-aminopropyl)-2-pyrrolidinone, etc.

Illustrative cycloaliphatic monoamines are those monoamines whereinthere is one cycloaliphatic substituent attached directly to the aminonitrogen through a carbon atom in the cyclic ring structure. Examples ofcycloaliphatic monoamines include cyclohexylamines, cyclopentylamines,cyclohexenylamines, cyclopentenylamines, N-ethyl-cyclohexylamine,dicyclohexylamines, and the like. Examples of aliphatic-substituted,aromatic-substituted, and heterocyclic-substituted cycloaliphaticmonoamines include propyl-substituted cyclohexylamines,phenyl-substituted cyclopentylamines, and pyranyl-substitutedcyclohexylamine.

Illustrative aromatic amines include those monoamines wherein a carbonatom of the aromatic ring structure is attached directly to the aminonitrogen. The aromatic ring will usually be a mononuclear aromatic ring(i.e., one derived from benzene) but can include fused aromatic rings,especially those derived from naphthalene. Examples of aromaticmonoamines include aniline, di-(para-methylphenyl)amine, naphthylamine,N-(n-butyl)-aniline, and the like. Examples of aliphatic-substituted,cycloaliphatic-substituted, and heterocyclic-substituted aromaticmonoamines are para-ethoxy-aniline, para-dodecylaniline,cyclohexyl-substituted naphthylamine, variously substitutedphenathiazines, and thienyl-substituted aniline.

Illustrative polyamines are aliphatic, cycloaliphatic and aromaticpolyamines analogous to the above-described monoamines except for thepresence within their structure of additional amino nitrogens. Theadditional amino nitrogens can be primary, secondary or tertiary aminonitrogens. Examples of such polyamines includeN-amino-propyl-cyclohexylamines, N,N′-di-n-butyl-paraphenylene diamine,bis-(para-aminophenyl)methane, 1,4-diaminocyclohexane, and the like.

Illustrative hydroxy-substituted amines are those having hydroxysubstituents bonded directly to a carbon atom other than a carbonylcarbon atom; that is, they have hydroxy groups capable of functioning asalcohols. Examples of such hydroxy-substituted amines includeethanolamine, di-(3-hydroxypropyl)-amine, 3-hydroxy butyl-amine,4-hydroxy butyl-amine, diethanolamine, di-(2-hydroxyamine,N-(hydroxypropyl)-propylamine, N-(2-methyl)-cyclohexylamine,3-hydroxycyclopentyl parahydroxy aniline, N-hydroxyethal piperazine andthe like.

In one embodiment, the amines are alkylene polyamines includinghydrogen, or a hydrocarbyl, amino hydrocarbyl, hydroxyhydrocarbyl orheterocyclic-substituted hydrocarbyl group containing up to about 10carbon atoms. Examples of such alkylene polyamines include methylenepolyamines, ethylene polyamines, butylene polyamines, propylenepolyamines, pentylene polyamines, hexylene polyamines, heptylenepolyamines, etc.

Alkylene polyamines include ethylene diamine, triethylene tetramine,propylene diamine, trimethylene diamine, hexamethylene diamine,decamethylene diamine, hexamethylene diamine, decamethylene diamine,octamethylene diamine, di(heptamethylene) triamine, tripropylenetetramine, tetraethylene pentamine, trimethylene diamine, pentaethylenehexamine, di(trimethylene)triamine, and the like. Higher homologs as areobtained by condensing two or more of the above-illustrated alkyleneamines are useful, as are mixtures of two or more of any of theafore-described polyamines.

Ethylene polyamines, such as those mentioned above, are especiallyuseful for reasons of cost and effectiveness. Such polyamines aredescribed in detail under the heading “Diamines and Higher Amines” inThe Encyclopedia of Chemical Technology, Second Edition, Kirk andOthmer, Volume 7, pages 27-39, Interscience Publishers, Division of JohnWiley and Sons, 1965, which is hereby incorporated by reference for thedisclosure of useful polyamines. Such compounds are prepared mostconveniently by the reaction of an alkylene chloride with ammonia or byreaction of an ethylene imine with a ring-opening reagent such asammonia, etc. These reactions result in the production of the somewhatcomplex mixtures of alkylene polyamines, including cyclic condensationproducts such as piperazines.

Other useful types of polyamine mixtures are those resulting fromstripping of the above-described polyamine mixtures. In this instance,lower molecular weight polyamines and volatile contaminants are removedfrom an alkylene polyamine mixture to leave as residue what is oftentermed “polyamine bottoms”. In general, alkylene polyamine bottoms canbe characterized as having less than 2, usually less than 1% (by weight)material boiling below about 200° C. In the instance of ethylenepolyamine bottoms, which are readily available and found to be quiteuseful, the bottoms contain less than about 2% (by weight) totaldiethylene triamine (DETA) or triethylene tetramine (TETA). A typicalsample of such ethylene polyamine bottoms obtained from the Dow ChemicalCompany of Freeport, Tex. designated “E-100”. Gas chromatographyanalysis of such a sample showed it to contain about 0.93% “Light Ends”(most probably DETA), 0.72% TETA, 21.74% tetraethylene pentamine and76.61% pentaethylene hexamine and higher (by weight). These alkylenepolyamine bottoms include cyclic condensation products such aspiperazine and higher analogs of diethylene triamine, triethylenetetramine and the like.

Illustrative dispersants are selected from: Mannich bases that arecondensation reaction products of a high molecular weight phenol, analkylene polyamine and an aldehyde such as formaldehyde; succinic-baseddispersants that are reaction products of a olefin polymer and succinicacylating agent (acid, anhydride, ester or halide) further reacted withan organic hydroxy compound and/or an amine; high molecular weightamides and esters such as reaction products of a hydrocarbyl acylatingagent and a polyhydric aliphatic alcohol (such as glycerol,pentaerythritol or sorbitol). Ashless (metal-free) polymeric materialsthat usually contain an oil soluble high molecular weight backbonelinked to a polar functional group that associates with particles to bedispersed are typically used as dispersants. Zinc acetate capped, alsoany treated dispersant, which include borated, cyclic carbonate,end-capped, polyalkylene maleic anhydride and the like; mixtures of someof the above, in treat rates that range from about 0.1% up to 10-20% ormore. Commonly used hydrocarbon backbone materials are olefin polymersand copolymers, i.e., ethylene, propylene, butylene, isobutylene,styrene; there may or may not be further functional groups incorporatedinto the backbone of the polymer, whose molecular weight ranges from 300tp to 5000. Polar materials such as amines, alcohols, amides or estersare attached to the backbone via a bridge.

The dispersant(s) are preferably non-polymeric (e.g., mono- orbis-succinimides). Such dispersants can be prepared by conventionalprocesses such as disclosed in U.S. Patent Application Publication No.2008/0020950, the disclosure of which is incorporated herein byreference.

The dispersant(s) can be borated by conventional means, as generallydisclosed in U.S. Pat. Nos. 3,087,936, 3,254,025 and 5,430,105.

Such dispersants may be used in an amount of about 0.01 to 20 weightpercent or 0.01 to 10 weight percent, preferably about 0.5 to 8 weightpercent, or more preferably 0.5 to 4 weight percent. Or such dispersantsmay be used in an amount of about 2 to 12 weight percent, preferablyabout 4 to 10 weight percent, or more preferably 6 to 9 weight percent.On an active ingredient basis, such additives may be used in an amountof about 0.06 to 14 weight percent, preferably about 0.3 to 6 weightpercent. The hydrocarbon portion of the dispersant atoms can range fromC₆₀ to C₁₀₀₀, or from C₇₀ to C₃₀₀, or from C₇₀ to C₂₀₀. Thesedispersants may contain both neutral and basic nitrogen, and mixtures ofboth. Dispersants can be end-capped by borates and/or cyclic carbonates.Nitrogen content in the finished oil can vary from about 200 ppm byweight to about 2000 ppm by weight, preferably from about 200 ppm byweight to about 1200 ppm by weight. Basic nitrogen can vary from about100 ppm by weight to about 1000 ppm by weight, preferably from about 100ppm by weight to about 600 ppm by weight.

As used herein, the dispersant concentrations are given on an “asdelivered” basis. Typically, the active dispersant is delivered with aprocess oil. The “as delivered” dispersant typically contains from about20 weight percent to about 80 weight percent, or from about 40 weightpercent to about 60 weight percent, of active dispersant in the “asdelivered” dispersant product.

Antiwear Additives

The lubricating oil compositions include at least one antiwear agent.Examples of suitable antiwear agents include oil soluble amine salts ofphosphorus compounds, sulfurized olefins, metaldihydrocarbyldithio-phosphates (such as zinc dialkyldithiophosphates),thiocarbamate-containing compounds, such as thiocarbamate esters,thiocarbamate amides, thiocarbamic ethers, alkylene-coupledthiocarbamates, and bis(S-alkyldithiocarbamyl) disulfides.

Antiwear agents used in the formulating of the lubricating oil may beashless or ash-forming in nature. Preferably, the antiwear agent isashless. So called ashless antiwear agents are materials that formsubstantially no ash upon combustion. For example, non-metal-containingantiwear agents are considered ashless.

In one embodiment, oil soluble phosphorus amine antiwear agents includean amine salt of a phosphorus acid ester or mixtures thereof. The aminesalt of a phosphorus acid ester includes phosphoric acid esters andamine sails thereof; dialkyldithiophosphoric acid esters and amine saltsthereof, amine salts of phosphites; and amine salts ofphosphorus-containing carboxylic esters, ethers, and amides; andmixtures thereof. The amine salt of a phosphorus acid ester may be usedalone or in combination.

In one embodiment, oil soluble phosphorus amine salts include partialamine salt-partial metal salt compounds or mixtures thereof. In oneembodiment, the phosphorus compound further includes a sulfur atom inthe molecule. In one embodiment, the amine salt of the phosphoruscompound may be ashless, i.e., metal-free (prior to being mixed withother components).

The amines which may be suitable for use as the amine salt includeprimary amines, secondary amines, tertiary amines, and mixtures thereof.The amines include those with at least one hydrocarbyl group, or, incertain embodiments, two or three hydrocarbyl groups. The hydrocarbylgroups may contain 2 to 30 carbon atoms, or in other embodiments 8 to26, or 10 to 20, or 13 to 19 carbon atoms.

Primary amines include ethylamine, propylamine, butylamine,2-ethylhexylamine, octylamine, and dodecylamine, as well as such fattyamines as n-octylamine, n-decylamine, n-dodeclyamine, n-tetradecylamine,n-hexadecylamine, n-octadecylamine and oleyamine. Other useful fattyamines include commercially available fatty amines such as “Armeen™”amines (products available from Akzo Chemicals, Chicago, Ill.), such asArmeen C, Armeen O, Armeen OL, Armeen T, Armeen HT, Armeen S and ArmeenS D, wherein the letter designation relates to the fatty group, such ascoco, oleyl, tallow, or stearyl groups.

Examples of suitable secondary amines include dim ethylamine,diethylamine, dipropylamine, dibutylamine, diamylamine, dihexylamine,diheptylamine, methylethylamine, ethylbutylamine and ethylamylamine. Thesecondary amines may be cyclic amines such as piperidine, piperazine andmorpholine.

The amine may also be a tertiary-aliphatic primary amine. The aliphaticgroup in this case may be an alkyl group containing 2 to 30, or 6 to 26,or 8 to 24 carbon atoms. Tertiary alkyl amines include monoamines suchas tert-butylamine, tert-hexylamine, 1-methyl-1-amino-cyclohexane,tert-octylamine, tert-decylamine, tertdodecylamine,tert-tetradecylamine, tert-hexadecylamine, tert-octadecylamine,tert-tetracosanylamine, and tert-octacosanylamine.

In one embodiment, the phosphorus acid amine salt includes an amine withC₁₁ to C₁₄ tertiary alkyl primary groups or mixtures thereof. In oneembodiment the phosphorus acid amine salt includes an amine with C₁₄ toC₁₈ tertiary alkyl primary amines or mixtures thereof. In one embodimentthe phosphorus acid amine salt includes an amine with C₁₈ to C₂₂tertiary alkyl primary amines or mixtures thereof.

Mixtures of amines may also be used in the disclosure. In one embodimenta useful mixture of amines is “Primene™ 81 W” and “Primene™ JMT.”Primene™ 81R and Primene™ JMT (both produced and sold by Rohm & Haas)are mixtures of C₁₁ to C₁₄ tertiary alkyl primary amines and C₁₈ to C₂₂tertiary alkyl primary amines respectively.

In one embodiment, oil soluble amine salts of phosphorus compoundsinclude a sulfur-free amine salt of a phosphorus-containing compound maybe obtained/obtainable by a process comprising: reacting an amine witheither (i) a hydroxy-substituted di-ester of phosphoric acid, or (ii) aphosphorylated hydroxy-substituted di- or tri-ester of phosphoric acid.A more detailed description of compounds of this type is disclosed inInternational Application PCT/US08/051126.

In one embodiment, the hydrocarbyl amine salt of an alkylphosphoric acidester is the reaction product of a C₁₄ to C₁₈ alkylated phosphoric acidwith Primene 81RT™ (produced and sold by Rohm & Haas) which is a mixtureof C₁₁ to C₁₄ tertiary alkyl primary amines.

Examples of hydrocarbyl amine salts of dialkyldithiophosphoric acidesters include the reaction product(s) of isopropyl, methyl-amyl(4-methyl-2-pentyl or mixtures thereof), 2-ethylhexyl, heptyl, octyl ornonyl dithiophosphoric acids with ethylene diamine, morpholine, orPrimene 81R™, and mixtures thereof.

In one embodiment, the dithiophosphoric acid may be reacted with anepoxide or a glycol. This reaction product is further reacted with aphosphorus acid, anhydride, or lower ester. The epoxide includes analiphatic epoxide or a styrene oxide. Examples of useful epoxidesinclude ethylene oxide, propylene oxide, butene oxide, octene oxide,dodecene oxide, and styrene oxide. In one embodiment, the epoxide may bepropylene oxide. The glycols may be aliphatic glycols having from 1 to12, or from 2 to 6, or 2 to 3 carbon atoms. The dithiophosphoric acids,glycols, epoxides, inorganic phosphorus reagents and methods of reactingthe same are described in U.S. Pat. Nos. 3,197,405 and 3,544,465. Theresulting acids may then be salted with amines.

The dithiocarbamate-containing compounds may be prepared by reacting adithiocarbamate acid or salt with an unsaturated compound. Thedithiocarbamate containing compounds may also be prepared bysimultaneously reacting an amine, carbon disulfide and an unsaturatedcompound. Generally, the reaction occurs at a temperature from 25° C. to125° C.

Examples of suitable olefins that may be sulfurized to form thesulfurized olefin include propylene, butylene, isobutylene, pentene,hexane, heptene, octane, nonene, decene, undecene, dodecene, undecyl,tridecene, tetradecene, pentadecene, hexadecene, heptadecene,octadecene, octadecenene, nonodecene, eicosene or mixtures thereof. Inone embodiment, hexadecene, heptadecene, octadecene, octadecenene,nonodecene, eicosene or mixtures thereof and their dimers, trimers andtetramers are especially useful olefins. Alternatively, the olefin maybe a Diels-Alder adduct of a diene such as 1,3-butadiene and anunsaturated ester, such as, butylacrylate.

Another class of sulfurized olefin includes fatty acids and theiresters. The fatty acids are often obtained from vegetable oil or animaloil; and typically contain 4 to 22 carbon atoms. Examples of suitablefatty acids and their esters include triglycerides, oleic acid, linoleicacid, palmitoleic acid or mixtures thereof. Often, the fatty acids areobtained from lard oil, tall oil, peanut oil, soybean oil, cottonseedoil, sunflower seed oil or mixtures thereof. In one embodiment fattyacids and/or ester are mixed with olefins.

Polyols include diols, triols, and alcohols with higher numbers ofalcoholic OH groups. Polyhydric alcohols include ethylene glycols,including di-, tri- and tetraethylene glycols; propylene glycols,including di-, tri- and tetrapropylene glycols; glycerol; butane diol;hexane diol; sorbitol; arabitol; mannitol; sucrose; fructose; glucose;cyclohexane diol; erythritol; and penta-erythritols, including di- andtripentaerythritol. Often the polyol is diethylene glycol, triethyleneglycol, glycerol, sorbitol, penta erythritol or dipentaerythritol.

In an alternative embodiment, the ashless antiwear agent may be amonoester of a polyol and an aliphatic carboxylic acid, often an acidcontaining 12 to 24 carbon atoms. Often the monoester of a polyol and analiphatic carboxylic acid is in the form of a mixture with a sunfloweroil or the like, which may be present in the mixture from 5 to 95, inseveral embodiments from 10 to 90, or from 20 to 85, or 20 to 80 weightpercent of said mixture. The aliphatic carboxylic acids (especially amonocarboxylic acid) which form the esters are those acids typicallycontaining 12 to 24, or from 14 to 20 carbon atoms. Examples ofcarboxylic acids include dodecanoic acid, stearic acid, lauric acid,behenic acid, and oleic acid.

Illustrative antiwear additives useful in this disclosure include, forexample, metal salts of a carboxylic acid. The metal is selected from atransition metal and mixtures thereof. The carboxylic acid is selectedfrom an aliphatic carboxylic acid, a cycloaliphatic carboxylic acid, anaromatic carboxylic acid, and mixtures thereof.

The metal is preferably selected from a Group 10, 11 and 12 metal, andmixtures thereof. The carboxylic acid is preferably an aliphatic,saturated, unbranched carboxylic acid having from about 8 to about 26carbon atoms, and mixtures thereof.

The metal is preferably selected from nickel (Ni), palladium (Pd),platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), andmixtures thereof.

The carboxylic acid is preferably selected from caprylic acid (C8),pelargonic acid (C9), capric acid (C10), undecylic acid (C11), lauricacid (C12), tridecylic acid (C13), myristic acid (C14), pentadecylicacid (C15), palmitic acid (C16), margaric acid (C17), stearic acid(C18), nonadecylic acid (C19), arachidic acid (C20), heneicosylic acid(C21), behenic acid (C22), tricosylic acid (C23), lignoceric acid (C24),pentacosylic acid (C25), cerotic acid (C26), and mixtures thereof.

Preferably, the metal salt of a carboxylic acid comprises zinc stearate,silver stearate, palladium stearate, zinc palmitate, silver palmitate,palladium palmitate, and mixtures thereof.

The metal salt of a carboxylic acid is present in the engine oilcompositions of this disclosure in an amount of from about 0.01 weightpercent to about 5 weight percent, based on the total weight of thelubricating oil composition.

A metal alkylthiophosphate and more particularly a metal dialkyl dithiophosphate in which the metal constituent is zinc, or zinc dialkyl dithiophosphate (ZDDP) can be a useful component of the lubricating oils ofthis disclosure. ZDDP can be derived from primary alcohols, secondaryalcohols or mixtures thereof. ZDDP compounds generally are of theformula

Zn[SP(S)(OR¹)(OR²)]₂

where R¹ and R² are C₁-C₁₈ alkyl groups, preferably C₂-C₁₂ alkyl groups.These alkyl groups may be straight chain or branched. Alcohols used inthe ZDDP can be 2-propanol, butanol, secondary butanol, pentanols,hexanols such as 4-methyl-2-pentanol, n-hexanol, n-octanol, 2-ethylhexanol, alkylated phenols, and the like. Mixtures of secondary alcoholsor of primary and secondary alcohol can be preferred. Alkyl aryl groupsmay also be used.

Preferable zinc dithiophosphates which are commercially availableinclude secondary zinc dithiophosphates such as those available from forexample, The Lubrizol Corporation under the trade designations “LZ677A”, “LZ 1095” and “LZ 1371”, from for example Chevron Oronite underthe trade designation “OLOA 262” and from for example Afton Chemicalunder the trade designation “HITEC 7169”.

The ZDDP is typically used in amounts of from about 0.4 weight percentto about 1.2 weight percent, preferably from about 0.5 weight percent toabout 1.0 weight percent, and more preferably from about 0.6 weightpercent to about 0.8 weight percent, based on the total weight of thelubricating oil, although more or less can often be used advantageously.Preferably, the ZDDP is a secondary ZDDP and present in an amount offrom about 0.6 to 1.0 weight percent of the total weight of thelubricating oil.

Low phosphorus engine oil compositions are included in this disclosure.For such compositions, the phosphorus content is typically less thanabout 0.12 weight percent, preferably less than about 0.10 weightpercent, and most preferably less than about 0.085 weight percent, andin certain instances less than about 0.065 weight percent.

Other illustrative antiwear agents useful in this disclosure include,for example, zinc alkyldithiophosphates, aryl phosphates and phosphites,sulfur-containing esters, phosphosulfur compounds, and metal or ash-freedithiocarbamates.

The antiwear additive concentration in the lubricating oils of thisdisclosure can range from about 0.01 to about 5 weight percent,preferably about 0.1 to 4.5 weight percent, and more preferably fromabout 0.2 weight percent to about 4 weight percent, based on the totalweight of the lubricating oil.

Corrosion Inhibitors

The lubricating oil compositions include at least one corrosioninhibitor. Corrosion inhibitors are used to reduce the degradation ofmetallic parts that are in contact with the lubricating oil composition.Suitable corrosion inhibitors include aryl thiazines, alkyl substituteddimercaptothiodiazoles, alkyl substituted dimercaptothiadiazoles, andmixtures thereof.

Corrosion inhibitors are additives that protect lubricated metalsurfaces against chemical attack by water or other contaminants. A widevariety of these are commercially available. As used herein, corrosioninhibitors include antirust additives and metal deactivators.

One type of corrosion inhibitor is a polar compound that wets the metalsurface preferentially, protecting it with a film of oil. Another typeof corrosion inhibitor absorbs water by incorporating it in awater-in-oil emulsion so that only the oil touches the metal surface.Yet another type of corrosion inhibitor chemically adheres to the metalto produce a non-reactive surface. Examples of suitable additivesinclude zinc dithiophosphates, metal phenolates, basic metal sulfonates,fatty acids and amines. Such additives may be used in an amount of about0.01 to 5 weight percent, preferably about 0.01 to 1.5 weight percent.

Illustrative corrosion inhibitors include (short-chain) alkenyl succinicacids, partial esters thereof and nitrogen-containing derivativesthereof; and synthetic alkarylsulfonates, such as metaldinonylnaphthalene sulfonates. Corrosion inhibitors include, forexample, monocarboxylic acids which have from 8 to 30 carbon atoms,alkyl or alkenyl succinates or partial esters thereof, hydroxy-fattyacids which have from 12 to 30 carbon atoms and derivatives thereof,sarcosines which have from 8 to 24 carbon atoms and derivatives thereof,amino acids and derivatives thereof, naphthenic acid and derivativesthereof, lanolin fatty acid, mercapto-fatty acids and paraffin oxides.

Particularly preferred corrosion inhibitors are indicated below.Examples of monocarboxylic acids (C₈-C₃₀), Caprylic acid, pelargonicacid, decanoic acid, undecanoic acid, lauric acid, myristic acid,palmitic acid, stearic acid, arachic acid, behenic acid, cerotic acid,montanic acid, melissic acid, oleic acid, docosanic acid, erucic acid,eicosenic acid, beef tallow fatty acid, soy bean fatty acid, coconut oilfatty acid, linolic acid, linoleic acid, tall oil fatty acid,12-hydroxystearic acid, laurylsarcosinic acid, myritsylsarcosinic acid,palmitylsarcosinic acid, stearylsarcosinic acid, oleylsarcosinic acid,alkylated (C₈-C₂₀) phenoxyacetic acids, lanolin fatty acid and C₈-C₂₄mercapto-fatty acids.

Examples of polybasic carboxylic acids which function as corrosioninhibitors include alkenyl (C₁₀-C₁₀₀) succinic acids and esterderivatives thereof, dimer acid, N-acyl-N-alkyloxyalkyl aspartic acidesters (U.S. Pat. No. 5,275,749). Examples of the alkylamines whichfunction as corrosion inhibitors or as reaction products with the abovecarboxylates to give amides and the like are represented by primaryamines such as laurylamine, coconut-amine, n-tridecylamine,myristylamine, n-pentadecylamine, palmitylamine, n-heptadecylamine,stearylamine, n-nonadecylamine, n-eicosylamine, n-heneicosylamine,n-docosylamine, n-tricosylamine, n-pentacosylamine, oleylamine, beeftallow-amine, hydrogenated beef tallow-amine and soy bean-amine.Examples of the secondary amines include dilaurylamine,di-coconut-amine, di-n-tri decyl amine, dimyristylamine,di-n-pentadecylamine, dipalmitylamine, di-n-pentadecylamine,distearylamine, di-n-nonadecylamine, di-n-eicosylamine,di-n-heneicosylamine, di-n-docosylamine, di-n-tricosylamine,di-n-pentacosyl-amine, dioleylamine, di-beef tallow-amine,di-hydrogenated beef tallow-amine and di-soy bean-amine. Examples of theaforementioned N-alkylpolyalkyenediamines include: ethylenediamines suchas laurylethylenediamine, coconut ethylenediamine,n-tridecylethylenediamine-, myristylethylenediamine,n-pentadecylethylenedi amine, palmitylethylenediamine,n-heptadecylethylenediamine, stearylethylenediamine,n-nonadecylethylenediamine, n-eicosylethylenediamine,n-heneicosylethylenediamine, n-docosylethylendiamine,n-tricosylethylenediamine, n-pentacosylethylenediamine,oleylethylenediamine, beef tallow-ethylenediamine, hydrogenated beeftallow-ethylenediamine and soy bean-ethylenediamine; propylenediaminessuch as laurylpropylenediamine, coconut propylenediamine,n-tridecylpropylenediamine, myristylpropylenediamine,n-pentadecylpropylenediamine, palmitylpropylenediamine,n-heptadecylpropylenedi amine, stearylpropylenediamine,n-nonadecylpropylenediamine, n-eicosylpropylenediamine,n-heneicosylpropylenediamine, n-docosylpropylendiamine,n-tricosylpropylenediamine, n-pentacosylpropylenediamine, diethylenetriamine (DETA) or triethylene tetramine (TETA), oleylpropylenediamine,beef tallow-propylenediamine, hydrogenated beef tallow-propylenediamineand soy bean-propylenediamine; butylenediamines such aslaurylbutylenediamine, coconut butylenediamine,n-tridecylbutylenediamine-myristylbutylenediamine,n-pentadecylbutylenediamine, stearylbutylenediamine,n-eicosylbutylenediamine, n-heneicosylbutylenedia-mine,n-docosylbutylendiamine, n-tricosylbutylenediamine,n-pentacosylbutylenediamine, oleylbutylenediamine, beeftallow-butylenediamine, hydrogenated beef tallow-butylenediamine and soybean butylenediamine; and pentylenediamines such aslaurylpentylenediamine, coconut pentylenediamine,myristylpentylenediamine, palmitylpentylenediamine,stearylpentylenediamine, oleyl-pentylenediamine, beeftallow-pentylenediamine, hydrogenated beef tallow-pentylenediamine andsoy bean pentylenediamine.

Other illustrative corrosion inhibitors include2,5-dimercapto-1,3,4-thiadiazoles and derivatives thereof,mercaptobenzothiazoles, alkyltriazoles and benzotriazoles. Examples ofdibasic acids useful as corrosion inhibitors, which may be used in thepresent disclosure, are sebacic acid, adipic acid, azelaic acid,dodecanedioic acid, 3-methyladipic acid, 3-nitrophthalic acid,1,10-decanedicarboxylic acid, and fumaric acid. The corrosion inhibitorscan be a straight or branch-chained, saturated or unsaturatedmonocarboxylic acid or ester thereof which may optionally be sulfurizedin an amount up to 35% by weight. Preferably the acid is a C₄ to C₂₂straight chain unsaturated monocarboxylic acid. The preferredconcentration of this additive is from 0.001% to 0.35% by weight of thetotal lubricant composition. The preferred monocarboxylic acid issulfurized oleic acid. However, other suitable materials are oleic aciditself; valeric acid and erucic acid. An illustrative corrosioninhibitor includes a triazole as previously defined. The triazole shouldbe used at a concentration from 0.005% to 0.25% by weight of the totalcomposition. The preferred triazole is tolylotriazole which may beincluded in the compositions of the disclosure include triazoles,thiazoles and certain diamine compounds which are useful as metaldeactivators or metal passivators. Examples include triazole,benzotriazole and substituted benzotriazoles such as alkyl substitutedderivatives. The alkyl substituent generally contains up to 1.5 carbonatoms, preferably up to 8 carbon atoms. The triazoles may contain othersubstituents on the aromatic ring such as halogens, nitro, amino,mercapto, etc. Examples of suitable compounds are benzotriazole and thetolyltriazoles, ethylbenzotriazoles, hexylbenzotriazoles,octylbenzotriazoles, chlorobenzotriazoles and nitrobenzotriazoles.Benzotriazole and tolyltriazole are particularly preferred. A straightor branched chain saturated or unsaturated monocarboxylic acid which isoptionally sulfurized in an amount which may be up to 35% by weight; oran ester of such an acid; and a triazole or alkyl derivatives thereof,or short chain alkyl of up to 5 carbon atoms; n is zero or an integerbetween 1 and 3 inclusive; and is hydrogen, morpholino, alkyl, amido,amino, hydroxy or alkyl or aryl substituted derivatives thereof; or atriazole selected from 1,2,4 triazole, 1,2,3 triazole,5-anilo-1,2,3,4-thiatriazole, 3-amino-1,2,4 triazole,1-H-benzotriazole-1-yl-methylisocyanide, methylene-bis-benzotriazole andnaphthotriazole.

The corrosion inhibitors may be used in an amount of 0.01 to 5 wt %,preferably 0.01 to 1.5 wt %, more preferably 0.01 to 0.2 wt %, stillmore preferably 0.01 to 0.1 wt % (on an as-received basis) based on thetotal weight of the lubricating oil composition.

Viscosity Modifiers

Viscosity modifiers (also known as viscosity index improvers (VIimprovers), and viscosity improvers) can be included in the lubricantcompositions of this disclosure.

Viscosity modifiers provide lubricants with high and low temperatureoperability. These additives impart shear stability at elevatedtemperatures and acceptable viscosity at low temperatures.

Suitable viscosity modifiers include high molecular weight hydrocarbons,polyesters and viscosity modifier dispersants that function as both aviscosity modifier and a dispersant. Typical molecular weights of thesepolymers are between about 10,000 to 1,500,000, more typically betweenabout 20,000 to 1,200,000, and even more typically between about 50,000and 1,000,000.

Examples of suitable viscosity modifiers are linear or star-shapedpolymers and copolymers of methacrylate, butadiene, olefins, oralkylated styrenes. Polyisobutylene is a commonly used viscositymodifier. Another suitable viscosity modifier is polymethacrylate(copolymers of various chain length alkyl methacrylates, for example),some compositions of which also serve as pour point depressants. Othersuitable viscosity modifiers include copolymers of ethylene andpropylene, hydrogenated block copolymers of styrene and isoprene, andpolyacrylates (copolymers of various chain length acrylates, forexample). Specific examples include styrene-isoprene orstyrene-butadiene based polymers of 50,000 to 200,000 molecular weight.

Olefin copolymers are commercially available from Chevron OroniteCompany LLC under the trade designation “PARATONE®” (such as “PARATONE®8921” and “PARATONE® 8941”); from Afton Chemical Corporation under thetrade designation “HiTEC®” (such as “HiTEC® 5850B”; and from TheLubrizol Corporation under the trade designation “Lubrizol® 7067C”.Hydrogenated polyisoprene star polymers are commercially available fromInfineum International Limited, e.g., under the trade designation“SV200” and “SV600”. Hydrogenated diene-styrene block copolymers arecommercially available from Infineum International Limited, e.g., underthe trade designation “SV 50”.

The polymethacrylate or polyacrylate polymers can be linear polymerswhich are available from Evnoik Industries under the trade designation“Viscoplex®” (e.g., Viscoplex 6-954) or star polymers which areavailable from Lubrizol Corporation under the trade designation Asteric™(e.g., Lubrizol 87708 and Lubrizol 87725).

Illustrative vinyl aromatic-containing polymers useful in thisdisclosure may be derived predominantly from vinyl aromatic hydrocarbonmonomer. Illustrative vinyl aromatic-containing copolymers useful inthis disclosure may be represented by the following general formula:

A-B

wherein A is a polymeric block derived predominantly from vinyl aromatichydrocarbon monomer, and B is a polymeric block derived predominantlyfrom conjugated diene monomer.

In an embodiment of this disclosure, the viscosity modifiers may be usedin an amount of less than about 10 weight percent, preferably less thanabout 7 weight percent, more preferably less than about 4 weightpercent, and in certain instances, may be used at less than 2 weightpercent, preferably less than about 1 weight percent, and morepreferably less than about 0.5 weight percent, based on the total weightof the lubricating oil composition. Viscosity modifiers are typicallyadded as concentrates, in large amounts of diluent oil.

The viscosity modifiers may be used in an amount of 0 to 20 wt %,preferably 0.1 to 10 wt %, more preferably 0.5 to 7.5 wt %, still morepreferably 1 to 5 wt % (on an as-received basis) based on the totalweight of the lubricating oil composition.

As used herein, the viscosity modifier concentrations are given on an“as delivered” basis. Typically, the active polymer is delivered with adiluent oil. The “as delivered” viscosity modifier typically containsfrom 20 weight percent to 75 weight percent of an active polymer forpolymethacrylate or polyacrylate polymers, or from 8 weight percent to20 weight percent of an active polymer for olefin copolymers,hydrogenated polyisoprene star polymers, or hydrogenated diene-styreneblock copolymers, in the “as delivered” polymer concentrate.

Metal Passivators

The lubricating oil compositions include at least one metal passivator.The metal passivators/deactivators include, for example, benzotriazole,tolyltriazole, 2-mercaptobenzothiazole,dialkyl-2,5-dimercapto-1,3,4-thiadiazole;N,N′-disalicylideneethylenediamine,N,N′-disalicyli-denepropylenediamine; zinc dialkyldithiophosphates anddialkyl dithiocarbamates.

Some embodiments of the disclosure may further comprise a yellow metalpassivator. As used herein, “yellow metal” refers to a metallurgicalgrouping that includes brass and bronze alloys, aluminum bronze,phosphor bronze, copper, copper nickel alloys, and beryllium copper.Typical yellow metal passivators include, for example, benzotriazole,totutriazole, tolyltriazole, mixtures of sodium tolutriazole andtolyltriazole, and combinations thereof. In one particular andnon-limiting embodiment, a compound containing tolyltriazole isselected. Typical commercial yellow metal passivators includeIRGAMET™-30, and IRGAMET™-42, available from Ciba Specialty Chemicals,now part of BASE, and VANLUBE™ 601 and 704, and CUVAN™ 303 and 484,available from R.T. Vanderbilt Company, Inc.

The metal passivator concentration in the lubricating oils of thisdisclosure can range from about 0.01 to about 5.0 weight percent,preferably about 0.01 to 3.0 weight percent, and more preferably fromabout 0.01 weight percent to about 1.5 weight percent, based on thetotal weight of the lubricating oil.

Other Additives

The lubricating oil useful in the present disclosure may additionallycontain one or more of the other commonly used lubricating oilperformance additives including but not limited to polar agents,non-polar agents, ionic liquids, extreme pressure additives,anti-seizure agents, wax modifiers, fluid-loss additives, sealcompatibility agents, lubricity agents, anti-staining agents,chromophoric agents, defoamants, demulsifiers, emulsifiers, densifiers,wetting agents, gelling agents, tackiness agents, colorants, lipids(hydrophilic, lipophilic, amphiphilic), phospholipids, glycolipids,glycerophospholipids, lecithin, and others.

Conductivity agents useful in the present disclosure encompassmaterials, components, chemicals, or fluids having polar functionalgroups, generally comprising heteroatoms, such as e.g. O, N, P, S, B,halides, metals, and such polar functional groups generally comprisinge.g. esters, ethers, ketones, alcohols, alkoxides, aldehydes,carboxylates, carboxylic acids, carboxylate salts, sulfates, sulfones,sulfonates, sulfinates, heteroatom-metal salts, amine salts, amines,amides, imides, imines, hetero-aromatics, organometallics, and the like.Conductivity agents encompass materials, components, chemicals, orfluids, that increase the conductivity of a Comparative fluid by atangible quantity, e.g. an increment of +100 pS/m or more, when added tosuch Comparative fluid in an effective amount. Conductivity agents maybe used individually, or two or more in combination, as treatments ormodifiers to compositions of lubricants and work fluids.

An embodiment of this disclosure is the use of a polar basestock, suchas for example an ester, to control the dielectric constant of alubricating or working fluid composition, and consequently to providecontrol over the value of the conductivity-to-dielectric constant ratio.Such polar basestocks and similarly acting agents are known asdielectric agents. An additional embodiment is the combination of adielectric agent, such as for example a polar ester basestock, plus aconductivity agent, such as for example a detergent, with such acombination providing surprising control over obtaining desiredperformance values of the conductivity-to-dielectic constant ratio.Polar basestocks are typically classified as Group V basestocks, andcontain non-carbon heteroatoms such as, for example, O, N, S, P, whichimpart polarity characteristics to the basestock. A dielectric agentincreases the dielectric constant of a lubricating or working fluidcomposition by +0.02 units or more, when used at an effective amount.Also, effective amounts of a dielectric agent can increase thedielectric constant of a lubricating or working fluid composition by0.02 or more, by 0.04 or more, by 0.06 or more, by 0.08 or more, by 0.1or more, by 0.15 or more, and sometimes 0.2 or more, depending onconcentration. Conductivity agents can function as dielectric agents,and similarly dielectric agents can function as conductivity agents,depending on the concentration of said agent in a lubricating or workingfluid composition, and depending on the contribution to thecomposition's properties for conductivity or dielectric constant orboth.

For a review of many commonly used additives, see Klamann in Lubricantsand Related Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN0-89573-177-0. Reference is also made to “Lubricant Additives” by M. W.Ranney, published by Noyes Data Corporation of Parkridge, N J (1973);see also U.S. Pat. No. 7,704,930, the disclosure of which isincorporated herein in its entirety. These additives are commonlydelivered with varying amounts of diluent oil, that may range from 5weight percent to 50 weight percent.

The additives useful in this disclosure do not have to be soluble in thelubricating oils. Insoluble additives such as zinc stearate in oil canbe dispersed in the lubricating oils of this disclosure.

The types and quantities of performance additives used in combinationwith the instant disclosure in lubricant compositions are not limited bythe examples shown herein as illustrations.

Ionic Liquids (ILs)

Ionic liquids are so-called salt melts which are preferably liquid atroom temperature and/or by definition have a melting point <100° C. Theyhave almost no vapor pressure and therefore have no cavitationproperties. In addition, through the choice of the cations and anions inthe ionic liquids, the lifetime and lubricating effect of thelubricating oil are increased, and by adjusting the electricconductivity, these liquids can be used in equipment in which there isan electric charge buildup, e.g., electric vehicle powertrains. Suitablecations for ionic liquids include a quaternary ammonium cation, aphosphonium cation, an imidazolium cation, a pyridinium cation, apyrazolium cation, an oxazolium cation, a pyrrolidinium cation, apiperidinium cation, a thiazolium cation, a guanidinium cation, amorpholinium cation, a trialkylsulfonium cation or a triazolium cation,which may be substituted with an anion selected from the groupconsisting of [PF₆]⁻, [BF₄]⁻, [CF₃CO₂]³¹, [CF₃SO₃]⁻ as well as itshigher homologs, [C₄F₉—SO₃]³¹ or [C₈F₁₇—SO₃]⁻ and higherperfluoroalkylsulfonates, [(CF₃SO₂)₂N]⁻, [(CF₃SO₂)(CF₃COO)N]⁻,[R¹—SO₃]⁻, [R¹—O—SO₃]⁻, [R¹—COO]⁻, Cr⁻, Br⁻, [NO₃]⁻, [N(CN)₂]⁻, [HSO₄]⁻,PF_((6-x))R³ _(x) or [R¹R²PO₄]⁻ and the radicals R¹ and R² independentlyof one another are selected from hydrogen; linear or branched, saturatedor unsaturated, aliphatic or alicyclic alkyl groups with 1 to 20 carbonatoms; heteroaryl, heteroaryl-C₁-C₆-alkyl groups with 3 to 8 carbonatoms in the heteroaryl radical and at least one heteroatom of N, O andS, which may be combined with at least one group selected from C₁-C₆alkyl groups and/or halogen atoms; aryl-aryl C₁-C₆ alkyl groups with 5to 12 carbon atoms in the aryl radical, which may be substituted with atleast one C₁-C₆ alkyl group; R³ may be a perfluoroethyl group or ahigher perfluoroalkyl group, x is 1 to 4. However, other combinationsare also possible.

Ionic liquids with highly fluorinated anions are especially preferredbecause they usually have a high thermal stability. The water uptakeability may be reduced significantly by such anions, e.g., in the caseof the bis(trifluoromethylsutfonyl)imide anion. Illustrative ionicliquids include, for example, butylmethylpyrrolidiniumbis(trifluoromethylsulfonyl)imide (MBPimide), methylpropylpyrrolidiniumbis(trifluoromethylsulfonyl)imide (MPPimide), hexylmethylimidazoliumtris(perfluoroethyl)trifluorophosphate (HMIMPFET),hexylmethylimidazolium bis(trifluoromethylsulfonyl)imide (HMIMimide),hexylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide (HMP),tetrabutylphosphonium tris(perfluoroethyl)trifluorophosphate (BuPPFET),octylmethylimidazolium hexafluorophosphate (OMIM PF6), hexylpyridiniumbis(trifluoromethyl)sulfonylimide (Hpyimide), methyltrioctylammoniumtrifluoroacetate (MOAac), butylmethylpyrrolidiniumtris(pentafluoroethyl)trifluorophosphate (MBPPFET),trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide(HPDimide), i-ethyl-3-methylimidazolium ethyl sulfate (EMIM ethylsulfate), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(EMIMimide), 1-ethyl-2,3-dimethylimidazoliumbis(trifluoromethylsulfonyl)imide (EMMIMimide),N-ethyl-3-methylpyridinium nonafluorobutanesulfonate (EMPyflate),trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide,trihexyl(tetradecyl)phosphoniumbis(2,4,4-trifluoromethylpentyl)phosphinate,tributyl(tetradecyl)phosphonium dodecylbenzenesulfonate, and the like.

Other illustrative ionic liquids include, for example,1-ethyl-3-methylimidazolium dicyanamide, trihexyltetradecylphosphoniumbis(trifluoromethylsulfonyl)amide, trihexyl(tetradecyl)phosphoniumbis(2,4,4-trimethylpentyl)phosphinate, 1-methyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, and tetradecylammoniumbis(2-ethylhexyl) phosphate.

Cation/anion combinations leading to ionic liquids include, for example,dialkylimidazolium, pyridinium, ammonium and phosphonium, etc. withorganic anions such as sulfonates, imides, methides, etc., as well asinorganic anions such as halides and phosphates, etc., such that anyother combination of cations and anions with which a low melting pointcan be achieved is also conceivable. Ionic liquids have an extremely lowvapor pressure, depending on their chemical structure, are nonflammableand often have thermal stability up to more than 260° C. and furthermoreare also suitable as lubricants.

The respective desired properties of the lubricant oil are achieved withthe ionic liquids through a suitable choice of cations and anions. Thesedesirable properties include adjusting electrical conductivity of thelubricant to spread the area of use, increasing the service life andlubricating effect of the lubricant, and adjusting the viscosity toimprove the temperature suitability. Suitable cations for ionic liquidshave proven to be a phosphonium cation, an imidazolium cation, apyridinium cation or a pyrrolidinium cation which may be combined withan anion containing fluorine and selected frombis(trifluoromethylsulfonyl)imide, bis(perfluoroalkylsulfonyl)imide,perfluoroalkyl sulfonate, tris(perfluoroalkyl)methidenes,bis(perfluoroalkyl)imidenes, bis(perfluoroaryl)imides,perfluoroarylperfluoroalkylsulfonylimides and tris(perfluoro-alkyl)trifluorophosphate or with a halogen-free alkyl sulfate anion.

Ionic liquids useful in the present disclosure are those that aresoluble in hydrocarbon, hydrophobic-type, fluids (i.e. oil-soluble), andsoluble in suitable lubricating/working fluids. Ionic liquids that arealso useful in the present disclosure are those that are soluble inpolar, hydrophilic- or amphiphilic-type, fluids (e.g. esters, ethers,etc.), and soluble in suitable lubricating/working fluids. Further,ionic liquids useful in the present disclosure may also be used in solidor semi-solid lubricants such as e.g. greases.

In an embodiment, such ionic liquid additives may be used in an amountof about 0.1 to 10 weight percent, preferably 0.5 to 7.5 weight percent,more preferably about 0.75 to 5 weight percent.

Antistatic Additives

In electric vehicle powertrains, static electricity is generated,especially when the lubricant is in use. To reduce that hazard, aconductive antistatic additive can be added to and distributedthroughout the lubricating oil. This lubricating oil will thereby avoidreduction in its performance associated with local breakdown of the basestock and safety problems from static electric build-up.

A class of products called “antistatic fluids” or “antistaticadditives”, which also are petroleum distillates, can be added to adjustthe conductivity of a lubricant oil to safe levels, e.g., at or above100 pico-siemens per meter conductivity. Very small quantities of theseantistatic fluids are required to raise the conductivity to the desiredlevels, namely, some 10 to 30 milliliters per 1,000 gallons ofhydrocarbon.

According to another feature of the disclosure, the antistatic additiveis selected from a population of commercially available materials basedon the ability of the material's chemical compatibility with thelubricating oil and the cost effectiveness of adjusting the conductivityof the lubricating oil to the desired level for the lubricating oil'santicipated application.

Typical antistatic fluids are ExxonMobil™ Chemical's line ofde-aromatized hydrocarbon fluids known as Exxsol™ fluids. Representativefluids and their distillation points include Exxsol™ antistatic fluidshexane (65 IBP (° C.) min, 71 DP (° C.) max, and additive amount 30ml/1000 gal), D 40 (150 IBP (° C.) min, 210 DP (° C.) max, and additiveamount 30 ml/1000 gal), D 3135 (152 IBP (° C.) min, 182 DP (° C.) max,and additive amount 10 ml/1000 gal), and D 60 (177 IBP (° C.) min, 220DP (° C.) max, and additive amount 30 ml/1000 gal). The IBP is thetemperature at which 1% of the material is distilled, and the DP is thetemperature at which 96% of the material is distilled.

Other illustrative antistatic agents are based on long-chain aliphaticamines (optionally ethoxylated) and amides, quaternary ammonium salts(e.g., behentrimonium chloride or cocamidopropyl betaine), esters ofphosphoric acid, polyethylene glycol esters, or polyols. Additionalantistatic agents include long-chain alkyl phenols, ethoxylated amines,glycerol esters, such as glycerol monostearate, amides, glycols, andfatty acids.

The quantity of antistatic additive required to adjust the conductivityof the lubricating oil is determined by measuring the conductivity ofthe lubricating oil as the antistatic additive is mixed in and stoppingwhen the desired conductivity consistent with the application to bereached. The amount of antistatic additive mixed in will range between0.001% and 10% of the lubricating oil by weight, and preferentiallybetween 1% and 7.5% by weight, though it may be mixed in at a liquidvolume of between 10 and 100,000 parts per million.

Pour Point Depressants (PPDs)

Conventional pour point depressants (also known as lube oil flowimprovers) may be added to the lubricating oil compositions of thepresent disclosure if desired. These pour point depressant may be addedto lubricating compositions of the present disclosure to lower theminimum temperature at which the fluid will flow or can be poured.Examples of suitable pour point depressants include polymethacrylates,polyacrylates, polyarylamides, condensation products of haloparaffinwaxes and aromatic compounds, vinyl carboxylate polymers, andterpolymers of dialkylfumarates, vinyl esters of fatty acids and allylvinyl ethers. U.S. Pat. Nos. 1,815,022; 2,015,748; 2,191,498; 2,387,501;2,655, 479; 2,666,746; 2,721,877; 2,721,878; and 3,250,715 describeuseful pour point depressants and/or the preparation thereof. Suchadditives may be used in an amount of about 0.01 to 5 weight percent,preferably 0.1 to 3 weight percent, more preferably about 0.5 to 1.5weight percent.

Seal Compatibility Agents

The lubricating oil compositions can include at least one sealcompatibility agent. Seal compatibility agents help to swell elastomericseals by causing a chemical reaction in the fluid or physical change inthe elastomer. Suitable seal compatibility agents for lubricating oilsinclude organic phosphates, aromatic esters, aromatic hydrocarbons,esters (butylbenzyl phthalate, for example), and polybutenyl succinicanhydride. Such additives may be used in an amount of about 0.01 to 5weight percent, preferably 0.1 to 3 weight percent, more preferablyabout 0.5 to 1.5 weight percent.

Antifoam Agents

Antifoam agents may advantageously be added to lubricant compositions.These agents retard the formation of stable foams. Silicones and organicpolymers are typical antifoam agents. For example, polysiloxanes, suchas silicon oil or polydimethyl siloxane, provide antifoam properties.Antifoam agents are commercially available and may be used inconventional minor amounts along with other additives such asdemulsifiers; usually the amount of these additives combined is lessthan 1 weight percent and often less than 0.1 weight percent. In anembodiment, such additives may be used in an amount of about 0.01 to 5weight percent, preferably 0.1 to 3 weight percent, more preferablyabout 0.5 to 1.5 weight percent.

Friction Modifiers

The lubricating oil compositions can include at least one frictionmodifier. A friction modifier is any material or materials that canalter the coefficient of friction of a surface lubricated by anylubricant or fluid containing such material(s). Friction modifiers, alsoknown as friction reducers, or lubricity agents or oiliness agents, andother such agents that change the ability of base oils, lubricantcompositions, or functional fluids, to modify the coefficient offriction of a lubricated surface may be effectively used in combinationwith the base oils or lubricant compositions of the present disclosureif desired. Friction modifiers that lower the coefficient of frictionare particularly advantageous in combination with the base oils and lubecompositions of this disclosure.

Illustrative friction modifiers may include, for example, organometalliccompounds or materials, or mixtures thereof. Illustrative organometallicfriction modifiers useful in the lubricating engine oil compositions ofthis disclosure include, for example, molybdenum amine, molybdenumdiamine, an organotungstenate, a molybdenum dithiocarbamate, molybdenumdithiophosphates, molybdenum amine complexes, molybdenum carboxylates,and the like, and mixtures thereof. Similar tungsten based compounds maybe preferable.

Other illustrative friction modifiers useful in the lubricating engineoil compositions of this disclosure include, for example, alkoxylatedfatty acid esters, alkanolamides, polyol fatty acid esters, boratedglycerol fatty acid esters, fatty alcohol ethers, and mixtures thereof.

Illustrative alkoxylated fatty acid esters include, for example,polyoxyethylene stearate, fatty acid polyglycol ester, and the like.These can include polyoxypropylene stearate, polyoxybutylene stearate,polyoxyethylene isosterate, polyoxypropylene isostearate,polyoxyethylene palmitate, and the like.

Illustrative alkanolamides include, for example, lauric aciddiethylalkanolamide, palmic acid diethylalkanolamide, and the like.These can include oleic acid diethyalkanolamide, stearic aciddiethylalkanolamide, oleic acid diethylalkanolamide, polyethoxylatedhydrocarbylamides, polypropoxylated hydrocarbylamides, and the like.

Illustrative polyol fatty acid esters include, for example, glycerolmono-oleate, saturated mono-, di-, and tri-glyceride esters, glycerolmono-stearate, and the like. These can include polyol esters,hydroxyl-containing polyol esters, and the like.

Illustrative borated glycerol fatty acid esters include, for example,borated glycerol mono-oleate, borated saturated mono-, di-, andtri-glyceride esters, borated glycerol mono-sterate, and the like. Inaddition to glycerol polyols, these can include trimethylolpropane,pentaerythritol, sorbitan, and the like. These esters can be polyolmonocarboxylate esters, polyol dicarboxylate esters, and on occasionpolyoltricarboxylate esters. Preferred can be the glycerol mono-oleates,glycerol dioleates, glycerol trioleates, glycerol monostearates,glycerol distearates, and glycerol tristearates and the correspondingglycerol monopalmitates, glycerol dipalmitates, and glyceroltripalmitates, and the respective isostearates, linoleates, and thelike. On occasion the glycerol esters can be preferred as well asmixtures containing any of these. Ethoxylated, propoxylated, butoxylatedfatty acid esters of polyols, especially using glycerol as underlyingpolyol can be preferred.

Illustrative fatty alcohol ethers include, for example, stearyl ether,myristyl ether, and the like. Alcohols, including those that have carbonnumbers from C₃ to C₅₀, can be ethoxylated, propoxylated, or butoxylatedto form the corresponding fatty alkyl ethers. The underlying alcoholportion can preferably be stearyl, myristyl, C₁₁-C₁₃ hydrocarbon, oleyl,isosteryl, and the like.

The lubricating oils of this disclosure exhibit desired properties,e.g., wear control, in the presence or absence of a friction modifier.

Useful concentrations of friction modifiers may range from 0.01 weightpercent to 5 weight percent, or about 0.1 weight percent to about 2.5weight percent, or about 0.1 weight percent to about 1.5 weight percent,or about 0.1 weight percent to about 1 weight percent. Concentrations ofmolybdenum-containing materials are often described in terms of Mo metalconcentration. Advantageous concentrations of Mo may range from 25 ppmto 700 ppm or more, and often with a preferred range of 50-200 ppm.Friction modifiers of all types may be used alone or in mixtures withthe materials of this disclosure. Often mixtures of two or more frictionmodifiers, or mixtures of friction modifier(s) with alternate surfaceactive material(s), are also desirable.

Extreme Pressure Agents

The lubricating oil compositions can include at least one extremepressure agent (EP). EP agents that are soluble in the oil includesulfur- and chlorosulfur-containing EP agents, chlorinated hydrocarbonEP agents and phosphorus EP agents. Examples of such EP agents includechlorinated wax; sulfurized olefins (such as sulfurized isobutylene),organic sulfides and polysulfides such as dibenzyldisulfide,bis-(chlorobenzyl)disulfide, dibutyl tetrasulfide, sulfurized methylester of oleic acid, sulfurized alkylphenol, sulfurized dipentene,sulfurized terpene, and sulfurized Diels-Alder adducts;phosphosulfurized hydrocarbons such as the reaction product ofphosphorus sulfide with turpentine or methyl oleate; phosphorus esterssuch as the dihydrocarbon and trihydrocarbon phosphites, e.g., dibutylphosphite, diheptyl phosphite, dicyclohexyl phosphite, pentylphenylphosphite; dipentylphenyl phosphite, tridecyl phosphite, distearylphosphite and polypropylene substituted phenol phosphite; metalthiocarbamates such as zinc dioctyldithio carbamate and bariumheptylphenol diacid; amine salts of alkyl and dialkylphosphoric acids orderivatives; and mixtures thereof (as described in U.S. Pat. No.3,197,405).

The extreme pressure agents may be used in an amount of 0.01 to 5 wt %,preferably 0.01 to 1.5 wt %, more preferably 0.01 to 0.2 wt %, stillmore preferably 0.01 to 0.1 wt % (on an as-received basis) based on thetotal weight of the lubricating oil composition.

When lubricating oil compositions contain one or more of the additivesdiscussed above, the additive(s) are blended into the composition in anamount sufficient for it to perform its intended function. Typicalamounts of such additives useful in the present disclosure are shown inTable 1 below.

It is noted that many of the additives are shipped from the additivemanufacturer as a concentrate, containing one or more additivestogether, with a certain amount of base oil diluents. Accordingly, theweight amounts in the table below, as well as other amounts mentionedherein, are directed to the amount of active ingredient (that is thenon-diluent portion of the ingredient). The weight percent (wt %)indicated below is based on the total weight of the lubricating oilcomposition.

TABLE 1 Typical Amounts of Lubricating Oil Components ApproximateApproximate Compound wt % (Useful) wt % (Preferred) Antioxidant 0.01-5  0.1-1.5 Dispersant 0.01-20   0.1-10  Detergent 0.01-10   0.1-7.5Antiwear 0.01-5   0.5-4   Viscosity Modifier (solid  0-20 0.1-10 polymer basis) Corrosion Inhibitor 0.01-5   0.1-2   Metal Passivator0.01-5   0.1-1.5 Friction Modifier 0-5 0.1-1.5 Pour Point Depressant 0-50.01-1.5  Antifoam Agent 0-3 0.001-0.15  Extreme Pressure Agent 0-50.01-2   Anti-Static  0-10 0.1-5   Ionic Liquid  0-10 0.1-5  

These additives may be added independently but are usually precombinedin packages which can be obtained from suppliers of lubricant oiladditives. Additive packages with a variety of ingredients, proportionsand characteristics are available and selection of the appropriatepackage will take the requisite use of the ultimate composition intoaccount.

The following non-limiting examples are provided to illustrate thedisclosure.

Examples

Lubricating oil compositions were prepared as described herein.

The additive packages used in the comparative compositions (Table 2)included one or more additives in effective amounts. Additives used inthe compositions were one or more of an antioxidant, dispersant,detergent, antiwear agent, corrosion inhibitor, viscosity modifier, andmetal passivator. Optional additives were one or more of a pour pointdepressant, metal deactivator, seal compatibility additive, antifoamagent, extreme pressure agent, and friction modifier. For the inventiveexamples disclosed herein, the inventive example compositions used theadditive package identified by the comparative oil listed in therespective tables, with the appropriate comparative oil composition asrecited in Table 2.

TABLE 2 Comparative Oils; Compositions & Properties Comparative 3Comparative 4 Comparative 5 Comparative 6 Comparative 7 Comparative 8Comparative 9 Composition (Wt %) Basestocks Group II 40 40 40 Group III39 21 40 40 40 Group IV 60 77 5 94 36 Group V 10 10 10 5 5 AdditivePackage 11 9 23 10 15 1 19 Properties Ratio Conductivity/ 286 749 198027 628 1.5 8222 Dielectric Constant Conductivity, pS/m 694 1850 4910 621463 3.4 19240 Dielectric Constant 2.43 2.18 2.48 2.32 2.33 2.20 2.34Viscosity, KV100 4.88 5.39 6.24 4.82 5.34 4.06 10.76 Viscosity, KV4016.85 29.48 16.77 23.75 57.22

Lubricating oils for electric vehicle powertrains were prepared byblending at least one lubricating oil base stock selected from a GroupI, Group II, Group III, Group IV, Group V base oils, and combinationsthereof, with one or more lubricating oil additives selected from anantioxidant, a detergent, a dispersant, an antiwear additive, acorrosion inhibitor, a viscosity modifier, a metal passivator, a pourpoint depressant, a metal deactivator, a seal compatibility additive, anantifoam agent, an extreme pressure agent, a friction modifier, otherperformance additives, and combinations thereof.

Conductivity agents included in these examples are listed in Table A.

TABLE A Conductivity Agents Conductivity Agents Class Description IL-1Ionic Liquid (IL) 1-Ethyl-3-methylimidazolium dicyanamide IL-2 IonicLiquid (IL) Trihexyltetradecylphosphoniumbis(trifluoromethylsulfonyl)amide IL-3 Ionic Liquid (IL)Trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinateIL-4 Ionic Liquid (IL) Tributyl(tetradecyl)phosphoniumdodecylbenzenesulfonate IL-5 Ionic Liquid (IL)1-Methyl-3-butylimidazolium bis (trifluoromethanesulfonyl)imide IL-6Ionic Liquid (IL) Tetradecylammonium bis(2-ethylhexyl) phosphate PL-1phospholipid (PL) L-α-Phosphatidylcholine PL-2 phospholipid (PL)Lecithin FA-1 fatty acid (FA) Stearic Acid Disp-1 Dispersant (Disp)Alkyl Succinimide (nominal MW 4000) Disp-2 Dispersant (Disp)Zinc-modified alkyl succinimide Disp-3 Dispersant (Disp) AlkylSuccinimide (nominal MW 5000) Disp-4 Dispersant (Disp) Borated alkylsuccinimide (nominal MW 3000) Det-1 Detergent (Det) Ca alkyl salicylate(low base) Det-2 Detergent (Det) Ca alkyl salicylate (mixed bases) Det-3Detergent (Det) Ca sulfonate (neutral) ZDDP-1 Antiwear Zinc dialkyldithiophosphate Ester-1 Ester fluid Diethylhexyl azelate

Electrical conductivity increases to low-conductivity oil aredemonstrated in Table 3, where conductivity agents such as ionic liquids(IL-1, IL-3, IL-5, IL-6), phospholipids (PL-1, PL-2), and fatty acid(FA-1), were added to low-conductivity oil Comparative 3. Increases inconductivity of greater than +100 pS/m were obtained in all Examples 3.1to 3.10. Further, Examples 3.1 to 3.8 have ratios ofconductivity-to-dielectric constant of less than 1,000, and thus haveperformances with improved protection against battery charge drainage.Examples 3.9 and 3.10 demonstrate use of conductivity agents (IL-3,PL-2) at higher dose concentrations (about +0.3% or more, in thesecases) to achieve high conductivities in the performance space where theratio of conductivity-to-dielectric constant is equal to or greater than1,000, and thus have performances with improved protection againstbearing electrical discharge.

TABLE 3 Effect of Conductivity Agents on Oils withConductivity-to-Dielectric Constant Ratio >200 Compar- Exam- Exam- Exam-Exam- Exam- Exam- Exam- Exam- Exam- Exam- ative 3 ple 3.1 ple 3.2 ple3.3 ple 3.4 ple 3.5 ple 3.6 ple 3.7 ple 3.8 ple 3.9 ple 3.10 Composition(Wt %) Comparative 3 100 99.9 99.95 99.9 99.95 99.95 99.95 99.95 99.9599.5 99.5 Conductivity Agents IL-1 0.1 IL-3 0.05 0.1 0.5 IL-5 0.05 IL-60.05 PL-1 0.05 PL-2 0.05 0.5 FA-1 0.05 Properties Ratio Conductivity/286 708 385 479 662 376 644 528 595 1847 2286 Dielectric ConstantConductivity, pS/m 694 1650 900 1120 1550 880 1500 1230 1380 4360 5350Dielectric Constant 2.43 2.33 2.34 2.34 2.34 2.34 2.33 2.33 2.32 2.362.34

Electrical conductivity increases to moderate-conductivity oil aredemonstrated in Table 4, where conductivity agents such as ionic liquids(IL-1, IL-3), and phospholipid (PL-2), were added to moderateconductivity oil Comparative 4. Increases in conductivity of greaterthan +100 pS/m were achieved in Examples 4.1, 4.3, 4.4, and 4.5. Example4.2 illustrates that IL-3 requires a dose of greater than about +0.1% toachieve the desired +100 pS/m increase versus Comparative 4. Examples4.1 to 4.3 have ratios of conductivity-to-dielectric constant of lessthan 1,000, and thus have performances with improved protection againstbattery charge drainage. Examples 4.4 and 4.5 demonstrate use ofconductivity agents (IL-3, PL-2) at higher dose concentrations to obtainratios of conductivity-to-dielectric constant equal to or greater than1,000, and thus have performances with improved protection againstbearing electrical discharge.

TABLE 4 Effect of Conductivity Agents on Oils withConductivity-to-Dielectric Constant Ratio >700 Comparative 4 Example 4.1Example 4.2 Example 4.3 Example 4.4 Example 4.5 Composition (Wt %)Comparative 4 100 99.9 99.9 99.95 99.5 99.5 Conductivity Agents IL-1 0.1IL-3 0.1 0.5 PL-2 0.05 0.5 Properties Ratio Conductivity/ 749 954 854959 1204 2023 Dielectric Constant Conductivity, pS/m 1850 2090 1870 21002660 4450 Dielectric Constant 2.18 2.19 2.19 2.19 2.21 2.20

Electrical conductivity increases to higher-conductivity oil aredemonstrated in Table 5, where conductivity agents such as ionic liquids(IL-1, IL-2, IL-3, IL-4), and phospholipid (PL-2), were added tohigher-conductivity oil Comparative 5. Increases in conductivity ofgreater than +100 pS/m were achieved in Examples 5.1 to 5.7, and 5.9.Example 5.8 illustrates that PL-2 requires a dose of greater than about+0.05% to achieve the desired +100 pS/m increase versus Comparative 5.All Examples 5.1 to 5.9 demonstrate use of conductivity agents to obtainratios of conductivity-to-dielectric constant equal to or greater than1,000, and thus have performances with improved protection againstbearing electrical discharge.

TABLE 5 Effect of Conductivity Agents on Oils withConductivity-to-Dielectric Constant Ratio >1900 Comparative ExampleExample Example Example Example Example Example Example Example 5 5.15.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Composition (Wt %) Comparative 5 10099.9 99.5 99 99.9 99.9 99.5 99.9 99.95 99.5 Conductivity Agents IL-1 0.10.5 1 IL-2 0.1 IL-3 0.1 0.5 IL-4 0.1 PL-2 0.05 0.5 Properties RatioConductivity/ 1980 3310 3747 4117 2980 2844 3571 4064 1943 2810Dielectric Constant Conductivity, pS/m 4910 8210 9330 10210 7420 71108820 10160 4800 6940 Dielectric Constant 2.48 2.48 2.49 2.48 2.49 2.502.47 2.50 2.47 2.47

Table 6 illustrates that a selected dispersant, in combination with oneor more performance additives, or in combination with a selectedperformance additive package, increases the conductivity of a typicallubricating or working fluid. Example 6.2 illustrates that dispersantDisp-2 gives a surprisingly large increase in the conductivity of alow-conductivity oil Comparative 6, and obtains a ratio ofconductivity-to-dielectric constant of about 721, i.e. less than about1000, and thus has performance for improved protection against batterycharge drainage. Use of Disp-2 at a higher concentration in a suitablefinished lubricating or working fluid obtains ratios ofconductivity-to-dielectric constant equal to or greater than 1,000 andthus has performance with improved protection against bearing electricaldischarge.

TABLE 6 Effect of Dispersants as Conductivity Agents Comparative ExampleExample Example 6 6.1 6.2 6.3 Composition (Wt %) Comparative 6 100 9998.5 99.3 Conductivity Agents Disp-1 1.0 Disp-2 1.5 Disp-3 0.7Properties Ratio 27 286 721 259 Conductivity/ Dielectric ConstantConductivity, pS/m 62 694 1751 626 Dielectric Constant 2.32 2.43 2.432.42 Viscosity, KV100 4.82 4.88 4.91 4.87 Viscosity, KV40 16.8 16.8 17.216.8

Electrical conductivity versus time, in a test of service life underoxidation conditions, of lubricant Examples 6.1, 6.2, and 6.3, plus acomparative transmission fluid, Comparative 7, is listed in Table 7.Oils were oxidized using a modified version of the ASTM D4310 test,where temperature was maintained at 125 C, and test oil was sampled atperiodic intervals to measure acidity and conductivity. Typicaltransmission fluid Comparative 7 performed poorly with loss of controlover electrical conductivity, demonstrating a conductivity of 25,000pS/m after 984 hours time-on-test, i.e a conductivity increase ofgreater than 15-fold versus that of fresh fluid. In contrast to thecomparative transmission fluid Comparative 7, lubricant Examples 6.1,6.2, and 6.3 showed electrical conductivity control within the range ofless than about 6,000 pS/m over about 984 hours time-on-test, i.e. aconductivity increase of about 2-fold to 5-fold increase versus freshoil. Electrical conductivity control is important for maintainingbattery and oil life.

TABLE 7 Oxidation Performance of Oils with Dispersant ConductivityAgents Oxidation Life Comparative 7 Example 6.1 Example 6.2 Example 6.3Time, hrs 0 984 1134 0 984 1134 0 984 1134 0 984 1134 RatioConductivity/ 628 10504 3193 286 1664 1578 721 2259 1599 259 1012 968Dielectric Constant Conductivity, pS/m 1463 25000 7760 694 4110 39301751 5580 3980 626 2500 2400 Dielectric Constant 2.33 2.38 2.43 2.432.47 2.49 2.43 2.47 2.49 2.42 2.47 2.48 Viscosity (cP), 25 C. 35.5 43.466.81 24.2 31.0 43.5 25.8 31.7 32.94 24.6 35.5 33.06 TAN 1.51 3.03 5.900.43 0.78 0.56 0.70 0.77 0.72 0.51 1.04 1.19 Copper, ppm 0 >68 0 390 >62 0 41

Further regarding Table 7, oxidation of both the comparative and exampleoils beyond 984 hours to an extended time of 1134 hours demonstratedecreases in oxidized oil conductivity. These unexpected results areattributed to a process where soluble high-conductivity materials,derived from oxidation, are removed from solution by deposition, therebylowering the conductivity of the resulting oil compositions. Therefore,such a system of monitoring the conductivity, and other electricalproperties, of lubricants and working fluids under oxidizing conditionsconstitutes a novel sensor system for detecting the relative cleanlinessof such fluids in service and for detecting the deposition of insolublematerials onto available surfaces within the service or mechanicalenvironment.

Referring to Table 7, Examples 6.1, 6.2, and 6.3 have compositions inaccordance with Table 1 above. Comparative 7 transmission fluid is atypical automatic transmission fluid.

Other performance attributes of the electric vehicle powertrainlubricating oils during service live are also illustrated in Table 7.Fluid acidity, as measured by TAN influences electrical conductivity. Asoils degrade, TAN increases, and such increases contribute to electricalconductivity increases. Electrical conductivity control is important todecrease the chances of battery drain and electrical breakdown.

Total acid number (TAN) over time, in a test of service life underoxidation conditions, of lubricant Examples 6.1, 6.2, and 6.3, plus acomparative transmission fluid, Comparative 7, is listed in Table 7.Examples 6.1, 6.2, and 6.3 demonstrate good control over TAN, all lowerthan about 1.2 after 984 hours time-on-test. The comparativetransmission fluid, Comparative 7 demonstrates a TAN of about 3.0 after984 hours tim-on-test, which is a typical condemning limit forlubricating oils.

The effect of other additives on the electrical properties of lubricantcompositions are listed in Table 8a, and illustrate the effects ofborated dispersant (Disp-4, Example 8.1), salicylate detergents (Det-1and Det-2, Examples 8.2 and 8.3), sulfonate detergent (Det-3, Examples8.4 and 8.5), and a combination of sulfonate detergent and ZDDP antiwear(Det-3 & ZDDP-1, Example 8.6). The use of a polar fluid such as esterbase stock (Examples 8.7 and 8.8) illustrates the specific control overthe dielectric constant of the lubricant composition, and thus providesadditional control over the ratio of conductivity-to-dielectric constantas recited in this disclosure. Further, combinations of polar basestocksand other conductivity agents give additional control in order to obtaintargeted, desirable ratios of conductivity-to-dielectric constant. Amongthese examples of Table 8a, Examples 8.1, 8.2, 8.4, 8.7, and 8.8 hadratios of conductivity-to-dielectric constant of less that about 1,000,thus had performances with improved protection against battery chargedrainage. Examples 8.3, 8.5, and 8.6 had ratios ofconductivity-to-dielectric constant equal to or greater than about1,000, and thus had performances with improved protection againstbearing electrical discharge. Additional illustrative examples arelisted in Table 8b.

TABLE 8a Effect of Additives as Conductivity Agents Comparative ExampleExample Example Example Example Example Example Example 8 8.1 8.2 8.38.4 8.5 8.6 8.7 8.8 Composition (Wt %) Comparative 8 100 99 99 99 99 9696 75 45 Conductivity Agents Disp-4 1 Det-1 1 Det-2 1 Det-3 1 4 3 ZDDP-11 Ester-1 25 55 Properties Ratio Conductivity/ 1.5 583 120 1795 633 17163593 7.3 45 Dielectric Constant Conductivity, pS/m 3.4 1282 265 39501399 3810 7940 19 145 Dielectric Constant 2.20 2.20 2.21 2.20 2.21 2.222.21 2.62 3.21 Viscosity, KV100 4.06 4.18 4.09 4.10 4.12 4.31 4.25 3.663.33

TABLE 8b Illustrative Examples of Conductivity Agents Comparative 8Example 8.9 Example 8.10 Example 8.11 Example 8.12 Example 8.13 Example8.14 Composition (Wt %) Comparative 8 100 74 98 83 74 81 98 ConductivityAgents Disp-4 1 1 1 Det-1 1 1 Det-2 1 1 Det-3 3 ZDDP-1 1 1 Ester-1 25 1525 15 Properties Illustrative 1.5 <1000 <1000 <1000 >1000 >1000 >1000Ratio Conductivity/ Dielectric Constant

Table 9 lists lubricant compositions where conductivity agents wereuseful in modifying ratios of conductivity-to-dielectric constant wheresuch ratios are high, and in these examples, are greater than about8,000. Ionic liquids, IL-3 and IL-4, can be effectively used asconductivity agents over a range of concentrations of about 0.01% to 1%,and achieve ratios of conductivity-to-dielectric constant of from about8,323 up to about 26,413 (Examples 9.3 and 9.4). These examples (Table9) had ratios of conductivity-to-dielectric constant equal to or greaterthan about 1,000, and thus had performances with improved protectionagainst bearing electrical discharge.

TABLE 9 Effect of Conductivity Agents on Oils withConductivity-to-Dielectric Constant Ratio >8000 Comparative ExampleExample Example Example 9 9.1 9.2 9.3 9.4 Composition (Wt %) Comparative9 100 99.99 99 99.99 99 Conductivity Agents IL-3 0.01 1 IL-4 0.01 1Properties Ratio 8222 8983 17016 8323 26413 Conductivity/ DielectricConstant Conductivity, pS/m 19240 21020 42200 19560 65240 DielectricConstant 2.34 2.34 2.48 2.35 2.47 Viscosity, KV100 10.76 Viscosity, KV4057.22

In an embodiment, compatibility of the lubricating oils of thisdisclosure with an energized electrical or electronic component can bedetermined in accordance with the method disclosed in U.S. ApplicationPublication No. 2015/0355122, herein incorporated by reference withregard to such method. In particular, the method involves (a) contactinga test apparatus with lubricating oil; (b) applying an electricalcurrent to the test apparatus; and (c) monitoring the current flowthrough the test apparatus over time. The test apparatus includes atleast one pair of conductors separated by an insulator that does notextend across the whole of the opposing surfaces of the conductors. Theelectrical current is applied across the pair of conductors.

PCT and EP Clauses:

1. A lubricating oil for an electric vehicle powertrain, saidlubricating oil having a composition comprising: a lubricating base oilas a major component; an additive package, as a minor component,comprising one or more lubricating oil additives; and an effectiveamount of one or more conductivity agents, as a minor component; whereinthe lubricating oil has an electrical conductivity from about 10 pS/m toabout 20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, witha ratio of electrical conductivity-to-dielectric constant from about 5to about 10,000.

2. The lubricating oil of clause 1 for an electric vehicle powertrain,said lubricating oil having a composition comprising: at least about 70weight percent of a lubricating base oil; and from about 0.01 to about30 weight percent of an additive package, wherein the additive packagecomprises one or more lubricating oil additives selected from the groupconsisting of an antioxidant, a detergent, a dispersant, an antiwearagent, a corrosion inhibitor, a viscosity modifier, a metal passivator,a pour point depressant, a seal compatibility agent, an antifoam agent,an extreme pressure agent, a friction modifier, and mixtures thereof;and from about 0.01 to about 30 weight percent of a conductivity agent;wherein each weight percent is based on the total weight of thelubricating oil; and wherein the lubricating oil has an electricalconductivity from about 10 pS/m to about 20,000 pS/m, a dielectricconstant of about 1.6 to about 3.6, with a ratio of electricalconductivity-to-dielectric constant from about 5 to about 10,000, akinematic viscosity from about 2 cSt to about 20 cSt at 100° C., a totalacid number (TAN) less than about 3, less than about 200 ppm activesulfur, and a viscosity index (VI) greater than about 50.

3. The lubricating oil of clauses 1 and 2 having an electricalconductivity from about 200 pS/m to about 16,000 pS/m, a dielectricconstant of about 1.8 to about 3.5, with a ratio of electricalconductivity-to-dielectric constant from about 10 to about 8,000, akinematic viscosity from about 2 cSt to about 14 cSt at 100° C., a totalacid number (TAN) less than about 2, less than about 100 ppm activesulfur, and a viscosity index (VI) greater than about 100.

4. The lubricating oil of clauses 1 and 2 wherein the lubricating baseoil comprises: a blend of a Group IV base stock and a Group V basestock; a blend of a Group III base stock and a Group V base stock; ablend of a Group II base stock and a Group V base stock; or a blend of aGroup I base stock and a Group V base stock.

5. The lubricating oil of clauses 1 and 2 wherein the lubricating baseoil comprises: a blend of a PAO base stock and an alkylated naphthaleneor ester base stock; a blend of a GTL base stock and an alkylatednaphthalene or ester base stock; and a blend of Group II base stock andan alkylated naphthalene or ester base stock.

6. The lubricating oil of clauses 1 and 2 wherein the one or moreconductivity agents are selected from the group consisting of ionicliquids, phospholipids, fatty acids, dispersants, detergents, antiwearagents, polar basestock fluids, and mixtures thereof.

7. The lubricating oil of clauses 1 and 2 wherein the electric vehiclepowertrain is one or more of an electric motor, an electric drive motor,a transmission, a front axle, a rear axle, a gear box, a differential,gears, bearings, a battery, a capacitor, a generator, an alternator, aconverter, a kinetic energy accumulator, or a kinetic energy recoverysystem.

8. A method for producing a lubricating oil for an electric vehiclepowertrain, said method comprising:

providing at least one lubricating oil basestock as a major component;providing at least one additive package as a minor component, comprisingone or more lubricating oil additives;providing an effective amount of at least one conductivity agent as aminor component; andblending the at least one lubricating oil basestock, and the at leastone additive package, and the at least one conductivity agent to producethe lubricating oil;wherein the lubricating oil has an electrical conductivity from about 10pS/m to about 20,000 pS/m, a dielectric constant of about 1.6 to about3.6, and a ratio of electrical conductivity-to-dielectric constant fromabout 5 to about 10,000.

9. The method of clause 8, wherein said lubricating oil has acomposition comprising: at least about 70 weight percent of alubricating base oil; and from about 0.01 to about 30 weight percent ofan additive package, wherein the additive package comprises one or morelubricating oil additives selected from the group consisting of anantioxidant, a detergent, a dispersant, an antiwear agent, a corrosioninhibitor, a viscosity modifier, a metal passivator, a pour pointdepressant, a seal compatibility agent, an antifoam agent, an extremepressure agent, a friction modifier, and mixtures thereof; and fromabout 0.01 to about 30 weight percent of a conductivity agent; whereineach weight percent is based on the total weight of the lubricating oil;and wherein the lubricating oil has an electrical conductivity fromabout 10 pS/m to about 20,000 pS/m, a dielectric constant of about 1.6to about 3.6, with a ratio of electrical conductivity-to-dielectricconstant from about 5 to about 10,000, a kinematic viscosity from about2 cSt to about 20 cSt at 100° C., a total acid number (TAN) less thanabout 3, less than about 200 ppm active sulfur, and a viscosity index(VI) greater than about 50.

10. The method of clauses 8 and 9 wherein the lubricating oil has anelectrical conductivity from about 200 pS/m to about 16,000 pS/m, adielectric constant of about 1.8 to about 3.5, with a ratio ofelectrical conductivity-to-dielectric constant from about 10 to about8,000, a kinematic viscosity from about 2 cSt to about 14 cSt at 100°C., a total acid number (TAN) less than about 2, less than about 100 ppmactive sulfur, and a viscosity index (VI) greater than about 100.

11. The method of clauses 8 and 9 wherein the lubricating base oilcomprises: a blend of a Group IV base stock and a Group V base stock; ablend of a Group III base stock and a Group V base stock; a blend of aGroup II base stock and a Group V base stock; or a blend of a Group Ibase stock and a Group V base stock.

12. The method of clauses 8 and 9 wherein the lubricating base oilcomprises: a blend of a PAO base stock and an alkylated naphthalene orester base stock; a blend of a GTL base stock and an alkylatednaphthalene or ester base stock; and a blend of Group II base stock andan alkylated naphthalene or ester base stock.

13. The method of clauses 8 and 9 wherein the one or more conductivityagents are selected from the group consisting of ionic liquids,phospholipids, fatty acids, dispersants, detergents, antiwear agents,polar basestock fluids, and mixtures thereof.

14. The method of clauses 8-9 wherein the electric vehicle powertrain isone or more of an electric motor, an electric drive motor, atransmission, a front axle, a rear axle, a gear box, a differential,gears, bearings, a battery, a capacitor, a generator, an alternator, aconverter, a kinetic energy accumulator, or a kinetic energy recoverysystem.

All patents and patent applications, test procedures (such as ASTMmethods, UL methods, and the like), and other documents cited herein arefully incorporated by reference to the extent such disclosure is notinconsistent with this disclosure and for all jurisdictions in whichsuch incorporation is permitted.

When numerical lower limits and numerical upper limits are listedherein, ranges from any lower limit to any upper limit are contemplated.While the illustrative embodiments of the disclosure have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by thoseskilled in the art without departing from the spirit and scope of thedisclosure. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthherein but rather that the claims be construed as encompassing all thefeatures of patentable novelty which reside in the present disclosure,including all features which would be treated as equivalents thereof bythose skilled in the art to which the disclosure pertains.

The present disclosure has been described above with reference tonumerous embodiments and specific examples. Many variations will suggestthemselves to those skilled in this art in light of the above detaileddescription. All such obvious variations are within the full intendedscope of the appended claims.

1. A lubricating oil for an electric vehicle powertrain, saidlubricating oil having a composition comprising: a lubricating base oilas a major component; an additive package, as a minor component,comprising one or more lubricating oil additives; and an effectiveamount of one or more conductivity agents as a minor component, whereinthe lubricating oil has an electrical conductivity from about 10 pS/m toabout 20,000 pS/m, a dielectric constant of about 1.6 to about 3.6, anda ratio of electrical conductivity-to-dielectric constant from about 5to about 10,000.
 2. The lubricating oil of claim 1 wherein thelubricating oil has a ratio of electrical conductivity-to-dielectricconstant from about 5 to less than 1,000.
 3. The lubricating oil ofclaim 1 wherein the lubricating oil has a ratio of electricalconductivity-to-dielectric constant from about 1,000 to about 10,000. 4.The lubricating oil of claim 1 wherein the lubricating oil has anelectrical conductivity from about 200 pS/m to about 16,000 pS/m.
 5. Thelubricating oil of claim 1 wherein the lubricating oil has adielectrical constant from about 1.8 to about 3.5.
 6. The lubricatingoil of claim 1 wherein the lubricating oil has a kinematic viscosityfrom about 2 cSt to about 20 cSt at 100° C., a total acid number (TAN)less than about 3, less than about 200 ppm active sulfur, and aviscosity index (VI) greater than about
 50. 7. The lubricating oil ofclaim 1 wherein the lubricating oil has a kinematic viscosity from about2 cSt to about 14 cSt at 100° C., a total acid number (TAN) less thanabout 2, less than about 100 ppm active sulfur, and a viscosity index(VI) greater than about
 100. 8. The lubricating oil of claim 1 whereinthe lubricating base oil comprises a Group I, Group II, Group III, GroupIV, Group V base stock, or mixtures thereof.
 9. The lubricating oil ofclaim 1 wherein the lubricating base oil comprises: a blend of a GroupIV base stock and a Group V base stock; a blend of a Group III basestock and a Group V base stock; a blend of a Group II base stock and aGroup V base stock; or a blend of a Group I base stock and a Group Vbase stock.
 10. The lubricating oil of claim 1 wherein the lubricatingbase oil comprises: a blend of a PAO base stock and an alkylatednaphthalene or ester base stock; a blend of a GTL base stock and analkylated naphthalene or ester base stock; or a blend of a Group II basestock and an alkylated naphthalene or ester base stock.
 11. Thelubricating oil of claim 1 wherein the lubricating base oil comprises ablend of a PAO base stock having a kinematic viscosity of about 3 cSt toabout 250 cSt at 100° C., and an alkylated naphthalene or ester basestock having a kinematic viscosity of about 2 cSt to about 22 cSt at100° C.; wherein the lubricating oil has a kinematic viscosity fromabout 4 cSt to about 12 cSt at 100° C.
 12. The lubricating oil of claim11 wherein the PAO base oil is present in an amount from about 5 toabout 95 weight percent of the lubricating oil, and the alkylatednaphthalene or ester base oil is present in an amount from about 5 toabout 95 weight percent of the lubricating oil.
 13. The lubricating oilof claim 1 wherein the lubricating base oil is present in an amount offrom about 70 weight percent to about 95 weight percent, based on thetotal weight of the lubricating oil.
 14. The lubricating oil of claim 1wherein the additive package is present in an amount of from about 0.01to about 30 percent, based on the total weight of the lubricating oil.15. The lubricating oil of claim 1 wherein the additive packagecomprises one or more lubricating oil additives selected from the groupconsisting of an antioxidant; a detergent; a dispersant; an antiwearagent; a corrosion inhibitor; a viscosity modifier; a metal passivator;a pour point depressant; a seal compatibility agent; an antifoam agent,an extreme pressure agent; a friction modifier; and mixtures thereof.16. The lubricating oil of claim 1 wherein the one or more conductivityagents are present in an amount of from about 0.01 to about 30 weightpercent, based on the total weight of the lubricating oil.
 17. Thelubricating oil of claim 1 wherein the one or more conductivity agentsare selected from the group consisting of ionic liquids, phospholipids,fatty acids, dispersants, detergents, antiwear agents, polar basestockfluids, and mixtures thereof.
 18. The lubricating oil of claim 1 furtherincluding a dielectric agent.
 19. The lubricating oil of claim 18wherein the dielectric agent comprises a polar basestock fluid in anamount sufficient to increase the dielectric constant by about 0.02 ormore.
 20. The lubricating oil of claim 17 wherein the ionic liquids arepresent in an amount of from about 0.01 to about 10 weight percent. 21.The lubricating oil of claim 17 wherein the ionic liquid is selectedfrom the group consisting of 1-ethyl-3-methylimidazolium dicyanamide,trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide,trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate,tributyl(tetradecyl)phosphonium dodecylbenzenesulfonate,1-methyl-3-butylimidazolium bis (trifluoromethanesulfonyl)imide, andtetradecylammonium bis(2-ethylhexyl) phosphate.
 22. The lubricating oilof claim 17 wherein the phospholipid is L-α-phosphatidylcholine orlecithin.
 23. The lubricating oil of claim 17 wherein the fatty acid isstearic acid.
 24. The lubricating oil of claim 17 wherein the dispersantis selected from the group consisting of ashless alkyl succinimides,metal-modified alkyl succinimides, and mixtures thereof.
 25. Thelubricating oil of claim 24 wherein the metal of the metal-modifiedalkyl succinimides dispersant comprises zinc, boron, or mixturesthereof.
 26. The lubricating oil of claim 17 wherein the detergent isselected from the group consisting of metal alkyl salicylates, metalalkyl sulfonates, calcium alkyl salicylates, calcium alkyl sulfonates,low-base calcium alkyl salicylate, high-base calcium alkyl salicylate,neutral calcium alkyl sulfonates, and mixtures thereof.
 27. Thelubricating oil of claim 17 wherein the antiwear agent is zinc dialkyldithiophosphate.
 28. The lubricating oil of claim 17 wherein the polarbasestock fluid is diethylhexyl azelate diester.
 29. The lubricating oilof claim 1 wherein the electric vehicle powertrain is one or more of anelectric motor, an electric drive motor, a transmission, a front axle, arear axle, a gear box, a differential, gears, bearings, a battery, acapacitor, a generator, an alternator, a converter, a kinetic energyaccumulator, or a kinetic energy recovery system.
 30. A method forproducing a lubricating oil for an electric vehicle powertrain, saidmethod comprising: providing at least one lubricating oil basestock as amajor component; providing at least one additive package as a minorcomponent comprising one or more lubricating oil additives; providing aneffective amount of at least one conductivity agent as a minorcomponent; and blending the at least one lubricating oil basestock, andthe at least one additive package, and the at least one conductivityagent to produce the lubricating oil; wherein the lubricating oil has anelectrical conductivity from about 10 pS/m to about 20,000 pS/m, adielectric constant of about 1.6 to about 3.6, and a ratio of electricalconductivity-to-dielectric constant from about 5 to about 10,000. 31.The method of claim 30 wherein the lubricating oil has a ratio ofelectrical conductivity-to-dielectric constant from about 5 to less than1,000.
 32. The method of claim 30 wherein the lubricating oil has aratio of electrical conductivity-to-dielectric constant from about 1,000to about 10,000.
 33. The method of claim 30 wherein the lubricating oilhas an electrical conductivity from about 200 pS/m to about 16,000 pS/m.34. The method of claim 30 wherein the lubricating oil has adielectrical constant from about 1.8 to about 3.5.
 35. The method ofclaim 30 wherein the lubricating oil has a kinematic viscosity fromabout 2 cSt to about 20 cSt at 100° C., a total acid number (TAN) lessthan about 3, less than about 200 ppm active sulfur, and a viscosityindex (VI) greater than about
 50. 36. The method of claim 30 wherein thelubricating oil has a kinematic viscosity from about 2 cSt to about 14cSt at 100° C., a total acid number (TAN) less than about 2, less thanabout 100 ppm active sulfur, and a viscosity index (VI) greater thanabout
 100. 37. The method of claim 30 wherein the lubricating base oilcomprises a Group I, Group II, Group III, Group IV, Group V base stock,or mixtures thereof.
 38. The method of claim 30 wherein the lubricatingbase oil comprises: a blend of a Group IV base stock and a Group V basestock; a blend of a Group III base stock and a Group V base stock; ablend of a Group II base stock and a Group V base stock; or a blend of aGroup I base stock and a Group V base stock.
 39. The method of claim 30wherein the lubricating base oil comprises: a blend of a PAO base stockand an alkylated naphthalene or ester base stock; a blend of a GTL basestock and an alkylated naphthalene or ester base stock; and a blend of aGroup II base stock and an alkylated naphthalene or ester base stock; ablend of a Group II base stock and an alkylated naphthalene or esterbase stock; a blend of a Group III base stock and an alkylatednaphthalene or ester base stock.
 40. The method of claim 30 wherein thelubricating base oil comprises a blend of a PAO base stock having akinematic viscosity of about 4 cSt to about 250 cSt at 100° C., and analkylated naphthalene or ester base stock having a kinematic viscosityof about 2 cSt to about 22 cSt at 100° C.; wherein the lubricating oilhas a kinematic viscosity from about 4 cSt to about 12 cSt at 100° C.41. The method of claim 40 wherein the PAO base oil is present in anamount from about 5 to about 95 weight percent of the lubricating oil,and the alkylated naphthalene or ester base oil is present in an amountfrom about 5 to about 95 weight percent of the lubricating oil.
 42. Themethod of claim 30 wherein the lubricating base oil is present in anamount of from about 70 weight percent to about 95 weight percent, basedon the total weight of the lubricating oil.
 43. The method of claim 30wherein the additive package is present in an amount of from about 0.01to about 30 percent, based on the total weight of the lubricating oil.44. The method of claim 30 wherein the additive package comprises one ormore lubricating oil additives selected from the group consisting of anantioxidant; a detergent; a dispersant; an antiwear agent; a corrosioninhibitor; a viscosity modifier; a metal passivator; pour pointdepressant; a seal compatibility agent; an antifoam agent, an extremepressure agent; a friction modifier; and mixtures thereof.
 45. Themethod of claim 30 wherein the one or more conductivity agents arepresent in an amount of from about 0.01 to about 30 weight percent,based on the total weight of the lubricating oil.
 46. The method ofclaim 30 wherein the one or more conductivity agents are selected fromthe group consisting of ionic liquids, phospholipids, fatty acids,dispersants, detergents, antiwear agents, polar basestock fluids, andmixtures thereof.
 47. The method of claim 30 further including adielectric agent.
 48. The method of claim 47 wherein the dielectricagent comprises a polar basestock fluid in an amount sufficient toincrease the dielectric constant by about 0.02 or more.
 49. The methodof claim 46 wherein the ionic liquids are present in an amount of fromabout 0.01 to about 10 weight percent.
 50. The method of claim 46wherein the ionic liquids are selected from the group consisting of1-ethyl-3-methylimidazolium dicyanamide, trihexyltetradecylphosphoniumbis(trifluoromethylsulfonyl)amide, trihexyl(tetradecyl)phosphoniumbis(2,4,4-trimethylpentyl)phosphinate, tributyl(tetradecyl)phosphoniumdodecylbenzenesulfonate, 1-methyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, and tetradecylammoniumbis(2-ethylhexyl) phosphate.
 51. The method of claim 46 wherein thephospholipid is L-α-phosphatidylcholine or lecithin.
 52. The method ofclaim 46 wherein the fatty acid is stearic acid.
 53. The method of claim46 wherein the dispersant is selected from the group consisting ofashless alkyl succinimides, metal-modified alkyl succinimides, andmixtures thereof.
 54. The method of claim 53 wherein the metal of themetal-modified alkyl succinimides dispersant comprises zinc, boron, ormixtures thereof.
 55. The method of claim 46 wherein the detergent isselected from the group consisting of metal alkyl salicylates, metalalkyl sulfonates, calcium alkyl salicylates, calcium alkyl sulfonates,low-base calcium alkyl salicylate, high-base calcium alkyl salicylate,neutral calcium alkyl sulfonates, and mixtures thereof.
 56. The methodof claim 46 wherein the antiwear agent is zinc dialkyl dithiophosphate.57. The method of claim 46 wherein the polar basestock fluid isdiethylhexyl azelate diester.
 58. The method of claim 30 wherein theelectric vehicle powertrain is one or more of an electric motor, anelectric drive motor, a transmission, a front axle, a rear axle, a gearbox, a differential, gears, bearings, a battery, a capacitor, agenerator, an alternator, a converter, a kinetic energy accumulator, ora kinetic energy recovery system.